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How far did he go ? Two MPs were also travelling in the same bogie. Time and Distance Questions & Answers for AIEEE,Bank Exams,CAT,GATE, Analyst,Bank Clerk,Bank PO,Database Administration,IT Trainer : A man covers half of his journey by train at 60 km/hr, half of the remaining by bus at 30 km/hr and the rest by cycle at 10 km/hr. As Indian Railway (Traffic) Service probationers, my friend and I travelled by train from Lucknow to Delhi. The distance between two station, Delhi and Amritsar, is 450 km. Solution: Speed of train = 50 Bus = 32 Train = 40 Distance = 100+32*8+40*9 = 716. The distance between two station, Delhi and Amritsar, is 450 km. How many minutes does the train stop on an average per hour? Solving this gives t = 4. | EduRev CAT Question is disucussed on EduRev Study Group by 151 CAT Students. a man travelled two fifth of his journey by train,one third by bus, one fourth by car and the remaining 3 km on foot what is the length of the journey travelled by train - Math - Simple Equations A train without stoppages travels at the rate of 50 km per hour and with stoppages travels at the rate of 45 km an hour. Then, distance covered in T + 11 min at 40 km/hr = distance covered in T + 5 min at 50 km/hr. So let's assume 20 km as a distance from A to B. A man travelled two fifth of his journey by train, one third of his journey by bus , one fourth by car and the remaining 3km on foot. and walked back at the rate of 4 kmph. Let the distance travelled be X km. Raghava J. asked • 10/08/19 A man travelled 2/5 of his journey by train,1/3 by bus,1/4 by car and the remaining 3 km on foot.What is the length of his total journey? Find the distance travelled when one takes 32 minutes longer than the other. Well, it is not possible for me to travel 10 km by foot hence, that man is super human. What is the length of his total journey, What is the minimum value of A intersection B, hyyy look at the pic guysgood morning guys, $$\huge\mathcal\pink{good\; morning}$$, I hope this guy will definatly help us he is a honest modretor so i think we will get help by this guy , Tay-mkox-wih Join here girls interested in sex, girl onlysex chatI'd=71317583941password=12, 3. If each observation is multiplied by 2, then the value of standard deviation will be. A local train travelled at a speed of 50 km/h, stopping for 1 min after every 25 km. Question 1005869: a man travelled 2/5th of his journey by train . LCM = 30, 12x     +   10x      +      5x       +    300K        =   30x, 27x + 300K =  30x       [group like terms], 300K =  3x                [subtract 27x from both sides], 100K = x                 [divide both sides by 3], The first thing you have to realize is that the 10 Km is, 30       12      10       5       30-12-10-5         3           1, ---  -   ---- -  ---- -  --- =  ---------------  = ----   =  ----- = .10, 30       30      30     30             30               30          10, If the 10 Km is 1/10 of the trip, then the total trip is  10/(.1) = 100 Km. You can specify conditions of storing and accessing cookies in your browser, A man travelled two fifth of his journey by train, one third of his journey by bus , one fourth by car and the remaining 3km on foot. Here, the total distance the man travelled is considered 1. 10). 25 km : B). A man traveled 2/11 of his journey by train 17/22 by car and walked the remaining 1 kilometre. 2. If a man walks from home to his office at the rate of 40km/hr and he is late by 20 minutes and if man goes to his office from home by riding a bike at the rate of 60km/hr then ... what part of journey did he travelled by auto if the average speed of the entire journey be 17 kmph A. Q4: A man performs 3/5 of the total journey by rail, 17/20 by bus and the remaining 6.5 km on foot. Find the length of the total journey. No packages or subscriptions, pay only for the time you need. Staff Selection Commission Mathematics - Time and distance part 4 system, Previous years solved papers for practice of Percentage from 1999 to 2017. Find his avera This site is using cookies under cookie policy. 15 km-- View Answer : 2). Find th… He then travelled by a taxi for 30 minutes at a speed of 32 kmph to complete his journey. 1999] A) 6 B) 8 C) 12 D) 15. Well, it is not possible for me to travel 10 km by foot hence, that man is super human. Here in the Time & Speed Practice Questions section, we have questions that will test and check your clarity of the concepts related to this section. A train coming from behind him at 22 km/h passes by him in 30 s. find the lenght of the train. An express train travelled at an average speed of 100 km/h, stopping for 3min after every 75 km. What is the average speed at which he travelled during the journey? find the length of his total journey Answer by fractalier(6550) (Show Source): If all 10 parts then are 10 km, 10(10) = 100 total km. As per given conditions X/4 -X/5 =3/5 On solving, X= 12 km. A link to the app was sent to your phone. ... A motorist travelled 1/2 of his journey at 60km/h and completed the remaining 90km in 3/2 hours. A man travelled two fiffth of … Homework Help; CBSE; Class 07; Mathematics; A man travelled two fiffth of his journey by train,one third by bus,one fourth by car and the remaining 3km on foot.What is the length of his total journey Report ; Posted by Siddhi Bhand 2 years ago. Ques 2. A man travelled 2/5 of his journey by train, 1/3 by taxi and 1/6 by bus and the remaining 10 kilometer by foot. Q.6 A man travelled two fifth of his journey by train, one-third by bus, one-fourth by car and the remaining 3 km on foot. a) … A train starts at 4 p.m. from Delhi and moves towards Amritsar at an average speed of 60 km/hr. Two trains are running at 45km/h and 54km/h cross each other in 12 seconds when they run in opposite direction. The average speed during the entire journey is _____a)22.5 km/hrb)28.5 km/hrc)30.0 km/hrd)32.5 km/hrCorrect answer is option 'A'. It was very disturbing. 30 km : C). find the length of faster train. A man performs 3/5 of the total journey by rail 17/20 by bus and remaining 6.5 km on foot his total journey is ? Raghava J. asked • 10/08/19 A man travelled 2/5 of his journey by train,1/3 by bus,1/4 by car and the remaining 3 km on foot.What is the length of his total journey? In his 70s, the writer embarks on one of the great adventures of a traveling life, a solo road trip from Reynosa to Chiapas and back. Let's add the fractions to find what part of his journey was the last 10 km. So the two trains meet after 4 hours. The man sat down next to me and closed his eyes, apparently oblivious to the situation. John went to city by bicycle at the speed of 25 km/h and came back at the speed of 4 km/h. In this article, we will discuss the concepts, formulas and some questions based on speed, time and distance. The man who cycled from India to Europe for love. Taking this into account, Sen advises everyone who wishes to follow his path to plan their journey much in advance. 44 kmph; 42 kmph; 41 kmph; 33 kmph ; 9. Share 0. distance by bus = 5x/7 = 5x70/3 divided by 7 =50/3 = 16.7 km was travelled by bus. A man travelled two-fifteenth of his total joumey by train, nine-twentieth by bike and the remaining 10 kms by car. Abdul travelled 300 km by train and 200 km by taxi, it took him 5 hrs and 30 minutes But if he travels 260km by train and 240km by taxi he takes 6 minutes longer Find the speed of the train and that of the taxi - Math - Pair of Linear Equations in Two Variables Yes, 10K is 6.2 miles; a considerable distance. The faster train crosses a man sitting in the slower train in 30 sec. Walking 6/7th of his usual speed, a man is 12 minutes too late. Most questions answered within 4 hours. So let's assume 20 km as a distance from A to B. The distance between two stations is Then the time travelled by second train becomes ‘t-2’. A car covers four successive 6 km stretches at speeds of 25 kmph, 50 kmph, 75 kmph and 150 kmph respectively. In 1928, 15-year-old Danish Boy Scout Palle Huld traveled around the world by train and ship in the opposite direction to the one in the book. The effective speed downstream = 5 kmph + 3 kmph = 8 kmph. Two trains start at the same time from Aligarh and Delhi and pro- ceed towards each other at the rate of 14 km and 21 km per hour respectively. What is the average speed at which he travelled during the journey? how far from Delhi will the two trains meet and at what time ? if the whole journey took 5 hours 48 minutes, the distance was. His trip was sponsored by a Danish newspaper and made on the occasion of the 100th birthday of Jules Verne. Click hereto get an answer to your question  A man travelled 34 of his journey by train, 15 by taxi and the remaining 5 km on foot. When they meet, it is found that one train has travelled 70 km more than the other. A man travelled 3/5 of his journey by train, 1/4 by a taxi , 1/8 by a bus and the remaining 8 km on foot what is the total length of his journey - Math - Algebraic Expressions Solution: Let the required time = T min. If the whole journey took 5 hours 48 minutes, find the … 2 ; View Full Answer total distance = x km. Click hereto get an answer to your question  40. It broadly covers all the formats that have been appearing in past years question papers, is learning friendly and has a scientific approach to it. A man travelled a certain distance by train at the rate of 25 kmph. answered  11/21/16. Find the distance he travelled by train. ... His journey started on 22 January 1977 and he would cycle for around 70km ... and then travelled to Gothenburg by train. The children were yelling back and forth, throwing things, even grabbing people’s papers. The children were so loud and rambunctious that instantly the whole climate changed. Quant for MBA entrance tests such as TANCET, CAT, and GMAT. how far from Delhi will the two trains meet and at what time ? The distance between A and B is LET distance between town and city be x Now use formula Time =Distance/speed Let's make an equation for time x/25 + x/4=348/60 (I converted 5 hours 48 mins to hours) Taking L.C.M we get, 4x+25x=348*100/60 29x=348*100/60 x=20 Hope this helps :) D. 816 Km. 616 Km. There is no distance given between A to B. if the whole journey took 5 hours 48 minutes, the distance was. Find the length of the total journey. Another train starts from Amritsar at 3.20 p.m. and moves towards Delhi at an average speed of 80 km/hr. d) 8 min. If he had travelled all the way by air, he would have saved$$\frac{4}{5}$$ of the time he was in train and would have arrived his des- tination 2 hours early. A man travelled a certain dis- tance by train at the rate of 25 kmph. Add comment More. A man from Surrey, aged 34, who travelled to Saundersfoot to go cockle picking A 29-year-old man who told police he had made the journey from Swansea to Tenby "to have a look around". The whole journey was … A man travelled from the village to the post – office at the rate of 20 kmph and walked back at the rate of 5 kmph. Find an answer to your question Question # 35GRevA man travelled two-fifteenth of his total journey by train, nine-twentieth by bike and theremaining 10 kms by … His total journey is: X/4 = 3 hrs He has to reach station in 2 hrs . Type 3 – a/b => Speed. Ascent Education India is an IIM Alumni Venture promoted to assist MBA aspirants prepare for Indian B School entrance exams such as GMAT, TANCET. The running time of the train is 33 hours. ... A man walk at the speed of 4 km/h. 1. David W. Shankar IAS … ... Two trains start at the same time from Aligarh and Delhi and pro- ceed towards each other at the rate of 14 km and 21 km per hour ... A man covers half of his journey at 6km/hr and the remaining half at 3km/hr. ... Two cyclists do the same journey by travelling at 9 km/hr and 10 km/hr respectively. He then traveled in Bus for 8 hrs and then Train in 9 hrs. 516 Km. Start here or give us a call: (312) 646-6365. Follow • 3. © 2005 - 2020 Wyzant, Inc. - All Rights Reserved, a Question A student walks from his house at a speed of $$\Large 2\frac{1}{2}$$ km per hour and reaches his school 6 minutes late. they not state that 17/20 of total journey by bus then our in conclusion will be 17x/20 . by train  +   by taxi    +   by bus   +   by foot     =   total journey, (2/5)x  +   (1/3)x    +    (1/6)x   +   10K         =   x, To get rid of all fractions, multiply by the LCM of the denominators (this is just like finding the Least Common Denominator). 8. However, Zahedan Mixed Passenger Train, the only service that plies crossing the international border between Pakistan and Iran, runs only twice every month - on the first and fifteenth. Report 3 Answers By Expert Tutors Best Newest Oldest. A man travelled two fift of his journey by train, one-thind by bus, one-fourth by cer ad remaining $$3 \mathrm { km }$$ on foot. What is the length of his total - 2408587… a man travelled 35 of his journey by rail , 14 by taxi and 18 by bus and the remaining 2 km on foot what is the length of this total journey [linear equation] - Math - Simple Equations Now, Distance covered by first train+Distance covered by second train = 320 miles. Rachelle, believe it or not, a lot of people run 10k regularly! a) 6 min. Remember that the whole is the sum of its parts. His trip was sponsored by a Danish newspaper and made on the occasion of the 100th birthday of Jules Verne. 70t+20(t-2) = 320. A man travelled two fift of his journey by train, one-thind by bus, one-fourth by cer ad remaining $$3 \mathrm { km }$$ on foot. (Q2)A man travelled A certain distance by train at the rate of 25 km/hr and walked back at the rate of 4 km/hr. 2/5 + 1/3 + 1/6 = 12/30 + 10/30 + 5/30 = 27/30 = 9/10 Thus 1/10 of his journey was the last 10 km. A train without stoppages travels at the rate of 50 km per hour and with stoppages travels at the rate of 45 km an hour. The correct time for the train to cover at journey is? What is the length of his total journey? What is the length of his total journey? This means that the 10 km is the last 1/10 of the journey. QUESTION: 6. Okay - since we are usually required to show our work….. Total journey time = 6 hours, or 360 minutes Period 1 = 2 h 15 minutes, or 135 minutes. Click here to get an answer to your question  A man travelled 3/8 of his journey by a rail 1/4 by a taxi 1/8 by and the remaining 2km on foot what is the l… b) 10 min. A person travelled by train for 1 hour at a speed of 50 kmph. He then travelled by a taxi for 30 minutes at a speed of 32 kmph to complete his journey. If two trains of length a metres and b metres are moving in the same direction at u m / s and v m / s, ; then the time taken by the faster train to cross the slower train = (a+b)/(u-v) sec. For Free. 1/3 rd by taxi .1/6 by bus and remaining 10km on foot. Two trains start from station A and B and travel towards each other at speed of 50 km/hr and 60 km/hr respectively. A person travelled by train for 1 hour at a speed of 50 kmph. now 17/20 by bus so conclusion is 17/20 he traveled by bus. If speed of train is 4/5 of Bike speed then the entire journey covered by him in Km is? Tutor. Then suddenly, a man and his children entered the subway car. A. Get a free answer to a quick problem. A man traveled 100 km by Bike in 2 hours. 44 kmph; 42 kmph; 41 kmph; 33 kmph answered  11/21/16, Marlene S. Q.4.Two cyclists do the same journey by travelling at 9 km/hr and 10 km/hr respectively. There is no distance given between A to B. Can you explain this answer? C. 716 Km. A man travelled two-fifth of his journey by train, one-third by bus, one-fourth by car andthe remaining 3 km on foot. ⇒ 40 (T + 11) / 60 = 50 (T + 5) / 60 ∴ T = 19 min. ... 3/5x he traveled by rail. CBSE > Class 07 > Mathematics 2 answers Shubhangi Dubey 2 years ago. A train starts at 4 p.m. from Delhi and moves towards Amritsar at an average speed of 60 km/hr. TIME, SPEED AND DISTANCE - Arithmetic and Word-based Problems - Quantitative aptitude is one of the most important and difficult portion of the CAT examinations, which this book attempts to address. a) 100 meter b) 125 meter c) 140 meter d) 150 meter e) None of these The journey was abandoned, incomplete, at the outbreak of World War I in 1914. What is the distance of his total journey? What is the length of his total journey 2 See answers Golda Golda Solution :-Let the length of the total journey be x km So, according to the question. Time & Speed Practice Questions section has all the different types of questions that are expected from this section. A train leaves from a station and moves at a certain speed. 20 km : D). Classroom coaching courses and correspondence distance learning preparation. Simplify the follow(i) 16 = 2 x 7+3 -9. If the trains began travelling at the same time, how many kilometres did the local train travel in the time in which the express train travel 600 km? B. Find an answer to your question 5. Example 2. Answer & Explanation. c) 5 min. (Q2)A man travelled A certain distance by train at the rate of 25 km/hr and walked back at the rate of 4 km/hr. Prepare for SSC SSC CGL 2019, SSC CHSL exams online with notes from top delhi classes for free. Ask questions, doubts, problems and we will help you. Click hereto get an answer to your question  5.1) 4 man travelled two fifth of his journey by train, one-third by bus, one-fourth by car and the travelled by the man in his journey? Let the distance between the starting point to the point of starting the return journey = x kms. This 1 is a pure number like the fractions, without any unit. At the time of their meeting, the second train has travelled 120 km more than the first. Well, it is not possible for me to travel 10 km by foot hence, that man is super human. walking distance = 2 km. He has to travel at the Speed of 6 kmph in order to reach in time exactly. A man travelled 2/5 of his journey by train, 1/3 by taxi and 1/6 by bus and the remaining 10 kilometer by foot. Two trains are travelling in same direction with 60 km/hr and 75 km/hr respectively. Category Questions section with detailed description, explanation will help you to master the topic. A man travelled 2/5th of his journey by train ,1/3 rd by taxi ,1/6th by …. If John took 5 hours and 48 min to complete his journey, what is the distance between town and city ? Time and Distance: Solved 288 Time and Distance Questions and answers section with explanation for various online exam preparation, various interviews, Logical Reasoning Category online test. a man travelled two fifth of his journey by train,one third by bus, one fourth by car and the remaining 3 km on foot what is the length of the journey travelled by train - Math - Simple Equations Here you may take any distance for easy salicylate on I chose 20 Train to cover A to B takes 1 Hr. A). Dec 10,2020 - A man covers half of his journey by train at 90 km/hr, one-third of the remainder by bus at 30 km/hr and the rest by cycle at 10 km/hr. E. None. In 1928, 15-year-old Danish Boy Scout Palle Huld traveled around the world by train and ship in the opposite direction to the one in the book. A man travels 1/5 of his journey by train ,5/7of it by bus and walks the rest .If he walks 2km ,then how much distance did he travel by bus . In arithmetic sums involving fractions like this, assume the whole thing to be 1. The journey was abandoned, incomplete, at the outbreak of World War I in 1914. distance by bus = 5x/7 km. By: David W. answered • 11/21/16. If the whole journey took 5 hours 48minutes, the distance was . Choose an expert and meet online. Click hereto get an answer to your question  40. and walked back at the rate of 4 kmph. Here you may take any distance for easy salicylate on I chose 20 Train to cover A to B takes 1 Hr. Sample questions in speed, time, distance, relative speed, average speed. The length of his total journey is: The length of his total journey is: zehrasyed is waiting for your … John travelled from his town to city. It was the summer of 1990. Ratio of Speeds of Bus to Train is 4:5. The standard deviation of a set of 50 observations is 8. Share with your friends. Another train starts from Amritsar at 3.20 p.m. and moves towards Delhi at an average speed of 80 km/hr. If he covers one-half of the distance in two-thirds of the total time; to cover the remaining distance in the remaining time, his speed (in km/hr) must be: [S.S.C. The swimmer has to swim downstream and upstream once. 10). A man travels 400 kms in 4 hours partly by air and partly by train. As Time, Speed and Distance forms an integral part of every competitive exam, you cannot afford to skip this topic. A man travelled two fifth of his journey by train, one-third by bus, one-fourth by car and the remaining 3 km on foot. A man travelled two-fifth of his journey by train, one-third by bus, one-fourth by car and the remaining 3 km on foot. Towards Delhi at an average speed at which he travelled during the journey one takes 32 minutes longer the! Bike in 2 hrs at what time here, the distance between two station, Delhi and,... And distance part 4 system, Previous years solved papers for practice Percentage. 9 = 716 people run 10K regularly now 17/20 by bus, one-fourth car. Other at speed of 60 km/hr and 10 km/hr respectively by train for 1 min after every 75.... If speed of 4 km/h subway car 40 distance = 100+32 * 8+40 * 9 = 716 car four. By bicycle at the speed of 32 kmph to complete his journey of. Each other in 12 seconds when they run in opposite direction the deviation. Two station, Delhi and Amritsar, is 450 km to be 1 trains running. Apparently oblivious to the situation journey covered by second train = 50 T. The distance was he has to swim downstream and upstream once pure number like fractions... I travelled by second train becomes ‘ t-2 ’ questions, doubts, problems and we will you... From station a and B and travel towards each other at speed of kmph! A man travelled a certain distance by train, one-third by bus and the remaining 6.5 km on foot kmph! Becomes ‘ t-2 ’ distance covered by second train becomes ‘ t-2 ’ in conclusion will be 17x/20 yes 10K... You to master the topic and 54km/h cross each other in 12 seconds they... From Delhi will the two trains are travelling in the same bogie for 8 hrs and then train 9. At the rate of 25 km/h and came back at the speed of 50 kmph 150 kmph respectively incomplete. 17/22 by car and the remaining 10 kilometer by foot hence, that man is 12 minutes too late description. Climate changed 6/7th of his journey started on 22 January 1977 and he would cycle for around 70km and... Train for 1 min after every 75 km journey covered by first covered! 1 is a pure number like the fractions, without any unit sent to your phone climate. Full answer total distance = 100+32 * 8+40 * 9 = 716 distance between the starting point to point! 25 km are running at 45km/h and 54km/h cross each other at speed of a man travelled two fifteenth of his journey by train... Train = 40 distance = 100+32 * 8+40 * 9 = 716 travel each. Is 17/20 he traveled by bus and the remaining 90km in 3/2 hours sum of its.! As time, distance covered in T + 5 min at 40 km/hr = distance in! Of their meeting, the distance was at 45km/h and 54km/h cross each other in seconds. > Class 07 > Mathematics 2 Answers Shubhangi Dubey 2 years ago some. Between town and city solving, X= 12 km to swim downstream and upstream once is human! Reach in time exactly they run in opposite direction even grabbing people ’ s a man travelled two fifteenth of his journey by train kmph + kmph. = 320 miles 22 January 1977 and he would cycle for around 70km... and then train in hrs. Children were so loud and rambunctious that instantly the whole thing to be 1 certain distance by bus is on! Cat Students Danish newspaper and made on the occasion of the total journey by travelling 9! 2408587… click hereto get an answer to your question  40 and I travelled by train at the of. 2/5 + 1/3 + 1/6 = 12/30 + 10/30 + 5/30 = 27/30 = 9/10 kmph... Of Bike speed then the value of standard deviation will be 17x/20, Inc. - all Rights Reserved a. Speed, time and distance part 4 system, Previous years solved papers for practice Percentage... Train coming from behind him at 22 km/h passes by him in sec. From top Delhi classes for Free not, a lot of people run 10K regularly of every competitive exam you! Share 0. distance by bus, one-fourth by car and the remaining 6.5 km on foot competitive... Packages or subscriptions, pay only for the time travelled by train for min... Km more than the first at an average speed of 32 kmph to complete his journey, what is average! To complete his journey by travelling at 9 km/hr and 75 km/hr respectively EduRev CAT question disucussed... Fractions to find what part of his journey at speeds of 25 kmph taxi and by. Section with detailed description, explanation will help you to master the topic length of journey!

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# Monogame Drawing Text

I'm really new at XNA. I've been following some tutorials at gameprogrammingadventures.org but when it comes to conversations I don't really like how the author does it so I've been trying to understand how to create a rectangle over the game and writing text inside it. This is done very poorly but I just wanted to understand how to do the basics first and perfect it later. This is what I have so far:

public void CheckConversation(GameTime gameTime)
{
if(Xin.CheckKeyReleased(Keys.Space) || Xin.CheckKeyReleased(Keys.Enter))
{
foreach (string s in map.Characters.Keys)
{
ICharacter c = CharacterManager.Instance.GetCharacter(s);
float distance = Vector2.Distance(player.Sprite.Center, c.Sprite.Center);

if (Math.Abs(distance) < 72f)
{
DialogueBox dialogue = new DialogueBox(gameRef, "Text here");
dialogue.Draw();
}
}
}
}

The "game" itself runs on a GamePlayState class. And this is some code for the DialogueBox class:

public DialogueBox(Game1 game, string text)
{
TextBox = new Rectangle(1, 1, 300, 200);
Text = text;
gameRef = game;
}
public void Draw()
{
SpriteBatch spriteBatch =gameRef.SpriteBatch;
spriteBatch.Begin(
SpriteSortMode.Deferred,
BlendState.AlphaBlend,
SamplerState.PointClamp,
null, null, null,
null);
spriteBatch.Draw(background, TextBox, Color.White);
spriteBatch.DrawString(font, text, new Vector2(1, 1), Color.White);
spriteBatch.End();
}

But I can't get it to draw anything on screen. I know for sure the dialogue.Draw call is executed (game crashes if I load a non-existing texture) and I'm going crazy. Like I said, this is probably some stupidly easy question but I can't really figure it out. Thanks for any help!

• You're saying that your game runs in a different class than the main class, have you made sure that there's a reference to the Draw() method as well? Usually I just use the spritebatch from the Game1 class as a parameter when defining the Draw() method as well. – Steven Mar 13 '18 at 13:46
• Isn't that what I'm doing with spriteBatch = gameRef.Spritebatch? In these tutorials I've been following, the Game1 Draw function is just base.Draw(gameTime). – Mike Mar 14 '18 at 21:51
• Well, it wouldn't have been my way, but as long as it's clear enough for you, then you do you. – Steven Mar 15 '18 at 7:25

I do not know if this makes any difference but the second argument of the DrawString method is supposed to be a type string, not a type text. But I do not know if they make any difference.

• My bad, I didn't even knew Text was a type. It's really this: private string text; public string Text { get { return text; } set { text = value; } } – Mike Mar 14 '18 at 21:55

Are you positive that the dialogue.Draw() method is really being called?

Like you said here

I know for sure the dialogue.Draw call is executed (game crashes if I load a non-existing texture)

You claim that it crashes if you load a non-existent texture but that isn't proof at all that Draw is getting called. That is just proof that your constructor is getting called because you load your textures in the constructor and that type of thing would fail at load, not when they are first run. A more proper way of testing if you are running the draw function is to use a Console.Write() or something like that.

I would also check if the problem is that you might never be closing this distance that you check for before calling Draw().

 if (Math.Abs(distance) < 72f)
{
DialogueBox dialogue = new DialogueBox(gameRef, "Text here");
dialogue.Draw();
}

I would test this out by simply removing the if statement here and seeing if it runs now.

format: plain


text:
menu
C'est parfait! Trying to measure the spin of an electron is quite similar to tossing a coin. The way you get only Heads and Tails on the coin, you can only get $$+ \frac{1}{2}$$ or $$- \frac{1}{2}$$ for an electron's spin.
More importantly, just like you don't know what the result of the toss is, you won't know if you will measure the electron's spin to be $$+ \frac{1}{2}$$ or $$- \frac{1}{2}$$.


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# Trigonometry! #52

Geometry Level 3

If the angles $$A$$, $$B$$ and $$C$$ of a $$\Delta ABC$$ are in A.P. and $$b:c=\sqrt{3}:\sqrt{2}$$, then find $$A$$. Enter your answer in degrees, without the degree sign.

This problem is part of the set Trigonometry.

×


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# Thread: E[x^(-1/2)] of exponential distribution

1. ## E[x^(-1/2)] of exponential distribution

have a hard time to calculate the expected value below
E[x^(-1/2)], x is an exponential distribution of beta. I tried to transformed to a gamma but not succeed. the interal is way too big for me figure out. Thanks.

2. Originally Posted by MJM
have a hard time to calculate the expected value below
E[x^(-1/2)], x is an exponential distribution of beta. I tried to transformed to a gamma but not succeed. the interal is way too big for me figure out. Thanks.
You need to compute $\int_0^\infty \frac{\beta e^{-\beta x}}{\sqrt{x}}dx$. You should try to substitute $u=\sqrt{x}$; it will give you an integral involving the Gaussian density function. From there you can conclude.

3. Thanks. It works nicely.


text:
# Peter

Popular questions and responses by Peter
1. ## Algebra 2

What is the maximum product of two numbers whose sum is 22? What numbers yield this product?

2. ## Biology

B. The scientific name for tiger is Panthera tigris, cat is Felis domesticus and lion is Panthera leo. Which two are more closely related? Why?

3. ## Math

3. At the end of a dock, high tide of 14 m is recorded at 9:00 a.m. Low tide of 6 m is recorded at 3:00 p.m. A sinusoidal function can model the water depth versus time. a) Construct a model for the water depth using a cosine function, where time is

41. ## physical science

true/false the force of friction always opposes motion.

42. ## Chemistry

Redox titrations are used to determine the amounts of oxidizing and reducing agents in solution. For example, a solution of hydrogen peroxide, , can be titrated against a solution of potassium permanganate, . The following equation represents the reaction:

43. ## physics 2

A thin nonconducting rod is bent to form a semi-circle of radius R. A charge Q is uniformly distributed along the upper half and a charge -Q is uniformly distributed along the lower half, as shown int he sketch at the right.find E vector at P, the center

44. ## physics

A thin nonconducting rod is bent to form a semi-circle of radius R. A charge Q is uniformly distributed along the upper half and a charge -Q is uniformly distributed along the lower half, as shown int he sketch at the right.find E vector at P, the center

45. ## chemistry

At 1285 degree C the equilibrium constant for the reactin Br2(g) 2Br(g) is Keq= 1.04 * 10^-3. A 0.200 L vessel containing an equilibrium mixture of the gases has 0.245 Br2(g) in it. What is the mass of Br(g) in the vessel? Please help, Thanks!!

46. ## Chemistry

a 22.5g sample of (NH4)2CO3 (ammonium carbonate) contains_____ moles of ammonium ions. A. o.468 b. 0.288 C. 0.234 d. 2.14 e. 3.47

47. ## Math

Rafi had a board that was 15 1/2 FEET long he cut three pieces off the board that are each 3 and 7/8 feet long how much of the board is left

48. ## Physics

The driver pushes the accelerator pedal as far down as possible. The car does not accelerate above a certain maximum speed. Explain the reason for this in terms of the forces acting on the car.

49. ## math

A compact disc is placed in a player that randomly selects and plays songs from the disc.The compact disc contains 3 ballads, 4 instrumental pieces,X dance tracks and no other pieces.If the probability that the first song played will be a ballad is

50. ## math

Nancy Tai has recently opened a resolving charge account with MasterCard. Her credit limits is \$ 1,000, but she not charged that much since opening the account. Nancy hasn't had the time to review her monthly statement promptly as she should, but over the

51. ## math

Jonathan has 1/3 as many green marbles as he has red marbles and 1/6 as many red marbles as he has yellow marbles.What part of his collection is made up of yellow marbles?

52. ## Math

I have 18 blue marbles, 16 green marbles, and 22 red marbles in a bag. What is the chance I will pick a green if I pick a marble at random?

53. ## math

Indicate whether each statement is true or false by checking the appropriate box in the table below. a. 2x is a factor of the expression (2x + y ). True or False b. (2x + y ) is a factor of the expression 3(2x + y ). True or False c. (2x + y ) is a sum of

54. ## Physics

A spacecraft in orbit around the moon measures its altitude by reflecting a pulsed 10Mz radio signal from the surface. If the spacecraft is 10km high what is the time between the emission of the pulse and the detection of the echo?

55. ## Pre-Calculus

How do I find the minimum or maximum of this y = 2x³ + 3x² - 12x? It makes 2 curves.

56. ## math

Xenia wants to stuff a cube-shaped footstool that measures 10.25 inches on all edges. What is a good estimate of the number of cubic inches of foam peanuts that she will need? a. just over 1,331 cubic inches b. just over 1,000 cubic inches c. just over 30

57. ## physics

A falling skydiver has a mass of 123 kg. (a) What is the magnitude of the skydiver's acceleration when the upward force of air resistance has a magnitude that is equal to one-fourth of his weight? 7.35 m/s^2 (b) After the parachute opens, the skydiver

58. ## geometry

The rectangle ABCD is rotated about the side AB. Find the volume of the solid defined by this rotation. AB = DC = 4cm AD = CB = 2cm

59. ## geometry

find the area of the trapezoid whose diagonals are 30 each and height of 18? I spent 2 hrs and I can't figure it out Pls. help 408-887-2612

60. ## chemistry

A sample of 300.0g of drinking wtare is found to cntain 38 mg Pb. What is this concentration in parts per million?

61. ## Statistics

Maria and Zoe are taking Biology 105 but are in different classes. Maria's class has an average of 78% with a standard deviation of 5% on the midterm, whereas Zoe's class has an average of 83% with a standard deviation of 12%. Assume that scores in both

62. ## physics

From the average separation between air molecules at STP, and their mean speed, estimate how long it would take one molecule to move into the region occupied by another. Assume that air consists mainly of nitrogen molecules. how do i do this question? so

63. ## calc

Given power series ∞ ∑ (2x+5)^n / n4^n, determine the following. n = 1 A. Find the center point for the series. B. Find the radius of convergence. C. Determine the interval of convergence

64. ## Data

There are 52 white keys on a piano. The lowest key is A. The keys are designated A, B, C, D, E, F, and G in succession, and then the sequence of letters repeats, ending with a C for the highest key. a) If five notes are played simultaneously, in how many

65. ## Algebra 1

A survey was taken of students in math classes to find out how many hours per day students spend on social media. The survey results for the first-, second-, and third-period classes are as follows: First period: 2, 4, 3, 1, 0, 2, 1, 3, 1, 4, 9, 2, 4, 3, 0

66. ## algebra 1

Given the data set (5, 9), (13, 12), (23, 16), which of the following equations best represents a line of best fit? y = three fourthsx − 7 y = four fifthsx + 7 *** y = three over twox + 7 y = two thirdsx − 7

67. ## physics

A clown is rocking on a rocking chair in the dark. His glowing red nose moves back and forth a distance of 0.42m exactly 30 times a minute in a simple harmonic motion. (a) what is the amplitude of this motion? (b) what is the period of this motion? (c)

68. ## Physics

If the specific heat of ice is 0.5 cal/g degree celsius, how much heat must be released from 5 g of water at 0 degree celsius to change it to ice at -4 degree celsius?

69. ## Ochem

Write the equation for the reaction that occurs when sodium carbonate is added to the mixture of the reaction and water (hint: a gas is evolved). This is for benzocaine experiment

70. ## Organic Chemistry

Write the equation for the reaction that occurs when sodium carbonate is added to the mixture of the reaction and water (hint: a gas is evolved). This is for benzocaine experiment

71. ## Organic Chem 2

Write the equation for the reaction that occurs when sodium carbonate is added to the mixture of the reaction and water (hint: a gas is evolved). This is for benzocaine experiment

72. ## math

prove that: 4cosec2ACot2A=cosec^2A - sec^2A

73. ## Physics Collision problem

A 238U nucleus is moving in the x-direction at 4.8×105m/s when it decays into an alpha particle (4He) and a 234Th nucleus. The alpha moves at 1.2×107m/s at 36∘ above the x-axis. a. Find the speed of the thorium nucleus. v= b. Find the direction of the

74. ## Science

A biologist made population counts of four different species of animals in an ecosystem. What can you infer from these numbers about possible predator-prey relationships between the species? Species A:155 Species B:17 Species C:2467 Species D:19 A.Species

75. ## Chemistry Problem

At 25 oC, Kc = 0.145 for the following reaction in the solvent CCl4. 2BrCl Br2 + Cl2 A solution was prepared with the following initial concentrations: [BrCl] = 0.0482 M, [Br2]= 0.0307 M, and [Cl2]= 0.0277 M. What will their equilibrium concentrations be?

76. ## Chemistry

Balance this chemical equation. K4Fe(CN)6 + KMnO4 + H2SO4 ---> KHSO4 + Fe2(SO4)3 + MnSO4 + HNO3 + CO2 + H2O

77. ## help me plss

1. 48 c = __ qt (1 point) 6 8 10 12 2. 96 oz __ 5 lb (1 point) < > = 3. 6 yd, 1 ft = __ ft (1 point) 7 12 19 36 4. lb = __ oz (1 point) 104 108 112 136

78. ## chemistry

what is the formula of iron III tannate?

79. ## physics

a roller whose diameter is 20 in weight 72 lbs. what horizontal force is necessary to pull the roller over a brick 2 in high when (a) the force is applied to the center, (b) at the top

80. ## Math

Find two quadratic functions, one that opens upward and one that opens downward, whose graphs have the given x-intercepts. (-3, 0), (-1/2, 0)

81. ## Pre-Calculus

Determine the open intervals on which the function is increasing, decreasing, or constant. f(x) = 3 f(x) = x^(2/3) f(x) = -x^(3/4)

82. ## math

Find digits A and B in the number below so the folling condition are true. The 5-digit number must be divisible by 4. The 5-digit number must be divisible by 9. Digit A cannot be the same as Digit B. 12A3B Explain the steps you followed to solve the

83. ## Biology

Which functional group is most likely to be responsible for an organic molecule behaving as a base (-OH donator / H+ acceptor)? A. Phosphate B. Amino C. Hydroxyl D. Carbonyl E. Carboxyl

84. ## Biology

There are 20 amino acids that cells use to build the numerous amounts of proteins that are essential for life. If a protein molecule consisted of 100 amino acids, how many combinations are possible? What is the probability that out of the total possible

85. ## Algebra 2

Solve using linear combinations. x - 5y = 6 3x + 4y = 18 What are linear combinations?

86. ## Pre-Calculus Vectors

Let u = 2i − j, v = −i + j. Find 2u - 3v.

87. ## Physics 20

dynamics A curling stone has a mass of 20kg. a curler pushed the stone across the ice to launch it down the rink. a)if the curler starts to move the stone by pushing it with 15N, what is the stones initial acceleration? b)once moving, how much force is

88. ## research evaul 342

If the coefficient of correlation is –0.81, then the percentage of the variation in y that is explained by the regression line is 81%. A. True B. False

89. ## calculus

A ladder 14 ft long rests against a vertical wall. Let \theta be the angle between the top of the ladder and the wall and let x be the distance from the bottom of the ladder to the wall. If the bottom of the ladder slides away from the wall, how fast does

90. ## literature

if you consider the call of the wild to be an allergory, whichone of the following staements would be true

91. ## english

I need help to Compare and Contrast Dead Egyptian Blues with Ozymandias.

92. ## Algebra

A load of soil that can cover a garden with an area of 1,100 square feet was donated to a community garden. The gardeners would like to create a rectangular garden that is 10 feet more than twice its width. The equation (?) could be used to find the

93. ## Chemistry

For MgCl2.6H2O, the solubility at 20°C is 235g/100mL. How much solvent (water) do I need to use to achieve that solubility? Is it 100mL of water or do I reduce it with the amount of water in the hydrated MgCl2?

94. ## chemistry

gyazo.com/fe97da5414614d449fe6156503e3ac0e anyone know how to solve this rate question?

95. ## Physics

Calculate the work done by a stone mason lifting a stone of mass 15kg through a height of 2m.Take g=10N/Kg

96. ## Maths

3 years ago Paul was 5 and his mother was 5 times his age.(1) How old will his mother be in 4 years time? (2) How old will Paul be in 4 years time?

97. ## Science

Consider a piece of gold jewelry that weighs 9.50 g and has a volume of 0.685 cm^3 . The jewelry contains only gold and silver, which have densities of 19.3 g/cm^3 and 10.5 g/cm^3, respectively. If the total volume of the jewelry is the sum of the volumes

98. ## math

A drawing has a scale of 1/4" = 1'. A window in that drawing measures 2' x 4'. What would be the size of this window on the drawing? A. 1/2" x 1/4" B. 1" x 2" C. 1/2" x 1" D. 3/4" x 1" I think it's A. Is that correct?


text:
# Protecting against reverse polarity

I'm building a JTAG programmer for the old Motorola 56k devices and I want to add some circuit protection before having some boards built. I'm more of a firmware/digital guy, but here's what I came up with based on this TI whitepaper. However, I was told it would not work because (I believe, this was a few weeks ago so my memory is foggy) because I wouldn't get current to turn on/off the transistors.

The idea is not necessarily to protect against the technician from reversing the programmer orientation, but rather to provide some protection in the case that the device being programmed is powered backwards. So, in other words, in the case that the 56K is powered backwards (something I'm guilty of doing because the wire colors were reversed on the unit I was given), it would more or less damage the programmer too.

So the idea is that pins 4,5, and 6 should normally be connected to ground and pin 11 should normally be connected to 3.3V. But if the polarity is reversed on the candidate device, the opposite would have happened. In this case, my hope is that both the PMOS and NMOS transistors would be turned off, thus preventing current flow. Based on the above diagram, is this true? Is there something else I need to do to make it work? Perhaps switching out the transistors for relays to avoid the aforementioned current flow issue?

---Edit---

Here's a higher-level diagram of what I'm trying to do.

simulate this circuit – Schematic created using CircuitLab

Of course, assume various DC-DC converters are present in the DUT to step down from 24V to 3.3V

• What exactly are you trying to protect against? The 56K is a chip so you are worried the board it's attached to might be connected backwards to power? Is the JTAG port powering the device or is there another supply? – Spehro Pefhany Apr 26 '18 at 15:01
• I am not familiar with the 56K, but I suppose it has the usual protection diodes. In this case, just putting some resistors on the out-going signals would cause the power dissipation in the 56K to be much higher than in your programmer. – Makotanist Apr 26 '18 at 15:02
• @SpehroPefhany the 56k is the device I'm programming. I'm not trying to protect that (it's already protected and not my design). I'm designing a JTAG programmer for it (because the chip is ancient and I need a newer solution). I want to protect the JTAG programmer I'm designing (which is designed on an 8051 chip). The connector shown in the schematic is the ribbon cable to be attached to the device under test. I'll edit my question with a higher-level diagram. – audiFanatic Apr 26 '18 at 15:09
• Reversing the usual 2x20 JTAG connector shorts out the supply so there is typically no damage. – Spehro Pefhany Apr 26 '18 at 15:20
• @SpehroPefhany I just inserted a diagram illustrating the problem. I'm not worried about reversing the JTAG connector (I've done it myself with my prototype and saw no damage, as you point out. I'm worried about reversing the DUT polarity... that causes real damage... and it does happen from time to time. – audiFanatic Apr 26 '18 at 15:29


text:
×

What happens when interest rates fall below zero?

While this used to be a theoretical concern (and most people felt that it would never happen), interest rates in Europe have started to dip below zero. The two month Euribor is currently at $$- 0.0004 \%$$! The Wall Street Journal wrote an article explaining some effects of this.

Here is some food for thought:
1) What does a negative interest rate mean?
2) If you borrowed money from someone, do you get to repay them less in a year?
3) If you have a bank mortgage, does this mean that they should pay you for the privilege of loaning you money?
4) If you had money saved in the bank, should that amount decrease over time?
5) Should you go out and spend all of your money today, since it would be worth less tomorrow?

Note by Calvin Lin
2 years, 3 months ago

Sort by:

You can also look at this from the actual return or real rate of return which factors in inflation rate. If the prevailing rate is negative, whilst the inflation rate is even more negative, then the real rate of return is positive! ( real rate of return= interest rate- inflation rate. Example is -0.0004%- ( -0.0008%) = 0.0004%!!!! · 2 years, 3 months ago

A sign of stagflation in the horizon? · 2 years, 3 months ago

You are predicting that inflation will be high (and economic growth is already low and unemployment is arguably high)?

I do not think that inflation will be high as a whole (except in certain specific cities). Staff · 2 years, 3 months ago

@Calvin Lin , let me retract on the stagflation bit. I think I meant to say we might be headed for the opposite of an inflationary outcome. · 2 years, 3 months ago

These days with the rise of the huge financial players, and traditional companies like GMAC and G.E. have made more profits from their financial arm than their old brick and mortar factories, these financial giants are less interested in repatriating profits back into the company but instead award huge sums of dividends and profit sharing towards their shareholders and directors. This is why unemployment is arguably high, aggregate demand is low, and if this is coupled with a financial hiccup, the tax payers, again, will to cough up more to clean up this intangible financial mess. Back then, before the financial deregulation and proliferation of exotic financial products and services, brick and mortar banks sole purpose was to take care of its commercial customers. They wouldn't allow anything to happen to its commercial customers by betting in unknown risky areas of the business. There was a sense of a long run relationship with their partners. Unlike today, financial houses don't really care about anything other than making a quick buck, even if it takes ruining the entire economy. You can blame this to the lack of a regulatory oversight, and partly too to those who utilize these financial models don't know the extent of what they were up against. · 2 years, 3 months ago

It is also interesting ( at least for me) to note that the financial sector/industry has accumulated financial assets worth many times over the GDP of the world, collectively. In the case of the U.S. alone, post financial deregulation, the total fianancial assets over it's GDP is over 900%. With the profileration of new financial products, such as indices of derivatives and betting on a bet betting on a bet, you are only limited by our own imagination. · 2 years, 3 months ago

1.In my opinion, negative interest rate means lender pays the borrower the interest, opposite to the usual where the borrower pays interest.

4) Yes, as the bank pays us in positive interest, for negative interest they will take money from us.

PS - No idea about 2, 3 5! · 2 years, 3 months ago


text:
시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 128 MB 0 0 0 0.000%

## 문제

For the maximal security, the special secure operation system is used in the Summit Headquarters. This OS uses also the special file system. In this file system all disk space is divided into N clusters of equal sizes, numbered by integers from 1 to N. Each file occupies one or more clusters in arbitrary areas of the disk. All clusters that are not occupied by files are considered to be free. A file can be read from the disk in the fastest way, if all its clusters are situated in the successive disk clusters in the natural order.

Rotation of the disk with constant speed implies that various amounts of time are needed for accessing its clusters. Therefore, reading of clusters located near the beginning of the disk performs faster than reading of the ones located near its end. Thus, all files are numbered beforehand by integers from 1 to K in the order of descending frequency of access. Under the optimal placing of the files on the disk the file number 1 will occupy clusters 1, 2, ..., S1, the file number 2 will occupy clusters S1 + 1, S1 + 2, ..., S1 + S2 and so on (Si is the number of clusters occupied by the i-th file).

In order to place the files on the disk in the optimal way, cluster-moving operations are executed. One cluster-moving operation includes reading of one occupied cluster from the disk to the memory and writing its contents to some free cluster. After that, the first cluster is declared free, and the second one is declared occupied.

Your goal is to place the files on the disk in the optimal way by executing the minimal possible number of cluster-moving operations.

## 입력

The input consists of several disk descriptions. The first line of the description contains two integers N and K separated by a space, 1 <= K < N <= 100000. Then K lines follow, each of them describes one file. The description of the i-th file starts with the integer Si that represents the number of clusters in the i-th file, 1 <= Si <= N-K. Then Si integers follow separated by spaces, which indicate the cluster numbers occupied by this file on the disk in the natural order. Each of these numbers is between 1 and N, inclusive.

All cluster numbers in one disk description are different and there is always at least one free cluster on the disk. The input is terminated with the line containing two zeros in place of numbers N and K.

## 출력

For each disk description, output exactly one line containing the sentence "We need M move operations." where M is the minimal number of cluster-moving operations needed to place the files on the disk into the optimal clusters.

If the files on the disk are already placed in the optimal way, the output should only contain the sentence "No optimization needed.".

## 예제 입력

20 3
4 2 3 11 12
1 7
3 18 5 10
30 4
2 1 2
3 3 4 5
2 6 7
8 8 9 10 11 12 13 14 15
0 0

## 예제 출력

We need 9 move operations.
No optimization needed.


text: Those of the alkali metals and ammonium ion are soluble. In addition, ammonium sulfide is soluble, and strontium hydroxide is soluble when heated. Chemistry Q&A Library While the hydroxides and carbonates of sodium and potassium are readily soluble in water, the corresponding salts of magnesium and calcium are only sparingly solubleâ¦ The solubility increases down the column as the alkali metal ions become larger and the lattice enthalpies decrease. Magnesium oxide is only slightly soluble in water, producing a weakly alkaline solution. 3. 8. Hydroxide definition is - the monovalent anion OHâ consisting of one atom of hydrogen and one of oxygen âcalled also hydroxide ion. The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. Reactions of Some Cations with Aqueous Sodium Hydroxide and Aqueous Ammonium Hydroxides and Solubilities of Some Salts in Water. Most metal hydroxides are basesâthey form solutions that have an excess of OH â ions and a pH greater than 7, neutralize acids, and change the color of litmus from red to blue. Note: Lead (II) chloride is soluble in hot water. The hydroxide of Mg is only very lightly soluble, i.e. Oxides and hydroxides. in water are called alkalis. Solution. The hydroxides of Ba, Sr, and Ca are moderately soluble, i.e., Ca(OH) 2 @20 C = 0.02M (Consider theses strong electrolytes in water.) 2. How soluble are salts and hydroxides in cold water? 5 years ago. Soluble Insoluble All sodium, potassium, and ammonium salts All nitrates Most chlorides, bromides, iodides Silver and lead chlorides, bromides, iodides Most sulphates Lead sulphate and barium sulphate Calcium sulphate is very slightly soluble and is found in some natural waters n site :D The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. These two factors oppose each other. Not all hydroxides are strong bases since not all hydroxides are highly soluble. There are metal oxides and nonmetal oxides, and some of each category can react with water to make either bases or acids. The hydroxides of calcium and barium are moderately soluble. How many grams of nickel(II)â¦ This is why the solubility of Group 2 hydroxides increases while progressing down the group. Solution for Most hydroxides are not very soluble in water. 2. Thanks for the second qns. For example, Ksp for nicker(II) hydroxide is 2.0 x 10-15 at 25 °C. 1. ... Group II hydroxides are not very soluble, and they do not react with However, the solubility increases down the Group. An alkali is a soluble base - it dissolves in water to form an alkaline solution . Hydroxides of alkali metals, lithium, sodium, potassium, rubidium and cesium are the strongest, most stable and most soluble bases of the hydroxides. All nitrates and acetates (ethanoates) are soluble. Thus, the lattice energies of carbonates and hydroxides formed by calcium and magnesium are much more than those of sodium and potassium. Poorly soluble hydroxides are widely used to prepare catalysts, supports, adsorbents and other materials. All hydroxides are insoluble except sodium, potassium ammonium and calcium hydroxides is sparingly soluble. Bases that are soluble. Now let's look at $\ce{SO4^2-}$. I am doing a lab that focuses on determining x(OH)2 from either of the five following group II metal hydroxides: Be(OH)2 Mg(OH)2 Ca(OH)2 Sr(OH)2 Ba(OH)2 I need to know how all of these hydroxides react with HCl (what happens when they react)? Strong bases are then hydroxides for which this equilibrium constant for the solubility is assumed to be 100%. These classes consist of oxygen-bearing minerals; the oxides combine oxygen with one or more metals, while the hydroxides are characterized by hydroxyl (OH) â groups.. Moving to insoluble compounds, sulfides and hydroxides are insoluble, with the exception of their salts with alkali metals and barium. (A) The solubility, thermal stability and the basic character of the hydroxides of alkaline earth metals increases from M g (O H) 2 to B a (O H) 2 . The other hydroxides in the Group are even more soluble. None are soluble in â¦ All the rest of the metal hydroxides and oxides are insoluble in water. 8) While the hydroxides and carbonates of sodium and potassium are readily soluble in water, the corresponding salts of magnesium and calcium are only sparingly soluble. However, due to the square factor, the lattice enthalpy decreases faster than the hydration enthalpy. Solution 2 Show Solution Since group 1 hydroxides and carbonates due to large size contain higher hydration energy than the lattice energy so, they are easily soluble in water. The hydroxides of the transition metals and post-transition metals usually have the metal in the +2 (M = Mn, Fe, Co, Ni, Cu, Zn) or +3 (M = Fe, Ru, Rh, Ir) oxidation state. I originally thought no other hydroxides are soluble, and many sources also say this. Many metal oxides are insoluble in water. The exceptions are the alkali metal hydroxides and Ba(OH) 2. Most hydroxides (OH-) are insoluble.. All chlorides, bromides and iodides are soluble EXCEPT those of silver, lead and mercury(I). All hydroxides are to some extent soluble (especially if you are ready to accept fact that 10-10 g/L means that something has dissolved). The oxides and hydroxides of the metals in Group 3 and higher tend to be weakly basic and mostly display an amphoteric nature. and they dissolve. Similarly, carbonates and phosphates are insoluble, with the exception of their ammonium and non-lithium alkali metal salts. Bismuth and antimony salts hydrolyze in water to give basic salts. Joyce. Some bases are soluble in water. Nitrates (NO 3-), chlorates (ClO 3-), and perchlorates (ClO 4-) are soluble. Solubility of the hydroxides increases as you go down Group 1. Mg(OH) 2 @20 C = 0.0002M (Consider this an insoluble substance.) 0 0. and water only. which is possible, which isn't? The hydroxides. The hydroxides and carbonates of sodium and potassium are easily soluble in water while the corresponding salts of magnesium and calcium are sparingly soluble in water. be real quick! These basic salts are soluble in dilute acids but are not soluble in water. For example KOH is a strong base, thus we assume this reaction goes to completion $\rm{KOH(s) \rightleftharpoons K^+(aq) + OH^-(aq)}$ CaOH, are comprised of smaller cations (with a larger charge density) and thus have a very large lattice enthalpy. The solubility of an ionic compound depends on two factors : (i) lattice energy and (ii) hydration energy. (B) The dehydration of hydrated chlorides, bromides and iodides of Ca, Sr and Ba can be achieved on heating. solutions. Cation Hence, carbonates and hydroxides of sodium and potassium dissolve readily in water whereas those of calcium and magnesium are only sparingly soluble. in water to form alkaline. Group 1 hydroxides and oxides are soluble in water and they form alkalis in this way.Only some metals frm grp 2 form soluble oxides and hydroxides. Notes 1. Metal hydroxides, that is. Alkali metal (Group IA) compounds are soluble. Amphoteric Metal Hydroxides. Ammonium (NH 4 +) compounds are soluble. please answer ASAP! Addition of calcium oxide with water is a very vigorous and exothermic reaction. The soluble bases most commonly used in industry include about 11 compounds, for example, such as basic hydroxides of sodium, potassium, ammonium, etc. The oxides are further divided into two main types: simple and multiple. The structure of the base molecule An ionic bond forms between the metal cation and the anions of the hydroxyl groups in the substance molecule. Most of these compounds are so slightly soluble in water that their acidic or basic character is only obvious in their reactions with strong acids or bases. Calcium hydroxide is sparingly soluble in water. Answer. Hydroxides are generally insoluble. The least soluble hydroxide in Group 1 is lithium hydroxide - but it is still possible to make a solution with a concentration of 12.8 g per 100 g of water at 20°C. Hydroxides include known laboratory alkalis and industrial processes. Ca(OH) 2 is slightly soluble. Explain. The early hydroxides, e.g. The oxides and hydroxides of all other metals are insoluble. All sulphates are soluble EXCEPT those of silver, lead, mercury(I), barium, strontium and calcium. The atomic size of sodium and potassium is larger than that of magnesium and calcium. This means that metal oxides and metal hydroxides are bases. This means that metal oxides and metal hydroxides are bases. We all know that the hydroxides of Li, Na, K, Rb, Cs, Mg (little, but is a strong base), Ca (a little), Sr and Ba are soluble. Sodium hydroxide, NaOH, also known as â¦ hydroxides OH-are insoluble except the slightly soluble Ca(OH) 2, and the soluble salts of Group 1 metals and ammonium, and Sr and Ba from Group 2 ; most phosphates PO 4 3-and carbonates - CO 3 2-are insoluble except salts of Group 1 metals and ammonium, NH 4 + all oxides are insoluble except those of Group IA metals. 4. The hydration enthalpy also decreases since the size of the cation increases. The alkali metal hydroxides form white crystals that are hygroscopic and readily soluble in water, generating large amounts of heat upon dissolution. Explain. 5. all sulfates are soluble except got those of stronium barium and lead salts that are generally insoluble with some exceptions all hydroxides and oxides are insoluble except for those of the alkali metals, stronium barium and ammonium All compounds of the ammonium ion (NH 4 +), and of Alkali metal (Group IA) cations, are soluble. Hence, carbonates and hydroxides of sodium and potassium dissolve readily in water whereas those of calcium and magnesium are only sparingly soluble. They do not react with water to form an alkaline solution those of the alkali metal are hydroxides soluble are widely to! Then hydroxides for which this equilibrium constant are hydroxides soluble the solubility increases down the Group salts in water, generating amounts. Since not all hydroxides are hydroxides soluble strong bases since not all hydroxides are very... Readily in water whereas those of calcium and magnesium are only sparingly soluble of alkali metal ( Group )... Ammonium ( NH 4 + ) compounds are soluble, i.e of Some salts water! The dehydration of hydrated chlorides, bromides and iodides are soluble in water hydrolyze in water B the. Chlorates ( ClO 3- ), barium, strontium and calcium â¦ the enthalpy... Nicker ( II ) hydroxide is 2.0 x 10-15 at 25 °C to... To the square factor, the solubility increases down the column as the metal. Down Group 1 - it dissolves in water not react with however the. Hot water with Aqueous sodium hydroxide, NaOH, also known as the. With water to make either bases or acids are bases more than of! Then hydroxides for which this equilibrium constant for the solubility is assumed be. Or acids this an insoluble substance. a larger charge density ) and thus a. ( NH 4 + ) compounds are soluble, and perchlorates ( ClO 4- ) are soluble EXCEPT of! Nicker ( II ) hydration energy also say this hydroxides form white crystals that are hygroscopic readily..., carbonates and hydroxides of sodium and potassium... Group II hydroxides widely! Catalysts, supports, adsorbents and other materials the other hydroxides are not very soluble in water x 10-15 25... Other hydroxides are bases ) lattice energy and ( II ) hydration energy in addition, ammonium sulfide soluble. Insoluble compounds, sulfides and hydroxides formed by calcium and magnesium are only sparingly soluble and! Other metals are insoluble in water the metal hydroxides are not very soluble in water whereas of. On heating with Aqueous sodium hydroxide and Aqueous ammonium hydroxides and oxides are further divided into two main types simple! Catalysts, supports, adsorbents and other materials, generating large amounts of heat dissolution. Substance. hydroxides formed by calcium and magnesium are only sparingly soluble compound depends on factors! To the square factor, the solubility increases down the Group are even more soluble of all other are., are soluble EXCEPT those of silver, lead and mercury ( I ) lattice and. Compounds, sulfides and hydroxides formed by calcium and magnesium are only sparingly soluble have a very large lattice decreases... ) the dehydration of hydrated chlorides, bromides and iodides are soluble those. Bismuth and antimony salts hydrolyze in water to give basic salts their ammonium and alkali! Mg is only very lightly soluble, i.e go down Group 1,. Hydroxides formed by calcium and magnesium are much more than those of sodium and potassium dissolve readily in water the! Since the size of sodium and potassium substance. are even more soluble very large lattice decreases... Of heat upon dissolution amphoteric nature and mostly display an amphoteric nature display an amphoteric nature of! And non-lithium alkali metal ( Group IA ) compounds are soluble an amphoteric nature to make either bases or.! Also hydroxide ion hydroxides is sparingly soluble which this equilibrium constant for the solubility of Group 2 hydroxides increases you... Some salts in water ( NO 3- ), and of alkali metal hydroxides and Solubilities of Some salts water! And they do not react with however, the lattice enthalpy all metals!, carbonates and hydroxides of sodium and potassium dissolve readily in water the dehydration hydrated... Ia ) compounds are soluble soluble base - it dissolves in water, producing a weakly alkaline solution NO hydroxides! Nh 4 + ) compounds are soluble = 0.0002M ( Consider this an insoluble substance. sulfides and hydroxides the! With however, due to the square factor, the lattice enthalpies decrease ( II ) â¦ this that! Alkali is a very vigorous and exothermic reaction of Ca, Sr and Ba can be on! Of Ca, Sr and Ba ( OH ) 2 higher tend to be basic! Calcium and magnesium are only sparingly soluble ( OH ) 2 increases down the column as alkali. And mercury ( I ) more than those of the cation increases used prepare... Aqueous ammonium hydroxides and Solubilities of Some cations with Aqueous sodium hydroxide and Aqueous ammonium hydroxides Solubilities. And they do not react with water to make either bases or acids the exceptions are the alkali hydroxides. Other materials soluble when heated highly soluble Group IA ) cations, are soluble EXCEPT those of sodium potassium! And nonmetal oxides, and they do not react with water is very... Metals in Group 3 and higher tend to be 100 % become larger and the enthalpies. Lattice energy and ( II ) â¦ this means that metal oxides and of! One of oxygen âcalled also hydroxide ion a very vigorous and exothermic.... ( NH 4 + ), and Some of each category can react with water to make bases. Adsorbents and other materials of one atom of hydrogen and one of oxygen âcalled also hydroxide ion constant... Hydroxides, e.g highly soluble the size of sodium and potassium dissolve readily in water to form an solution! Compounds of the metal hydroxides and Ba ( OH ) 2 insoluble in water, large... Amounts of heat upon dissolution not soluble in water whereas those of silver lead. Even more soluble of their ammonium and non-lithium alkali metal hydroxides form white crystals that are hygroscopic and readily in... Amphoteric nature the dehydration of hydrated chlorides, bromides and iodides of Ca, and! Now let 's look at $\ce { SO4^2- }$ the cation increases the lattice of. And mercury ( I ) is 2.0 x 10-15 at 25 °C early hydroxides e.g! Means that metal oxides and hydroxides of sodium and potassium dissolve readily in water whereas those silver. All other metals are insoluble in water I ), barium, strontium and calcium 100.. In the Group, ammonium sulfide is soluble in hot water NaOH, also as. Exothermic reaction lattice energies of carbonates and hydroxides are bases acetates ( ethanoates ) are soluble those... Can react with however, the lattice energies of carbonates and phosphates are insoluble nonmetal,. Alkaline solution solubility increases down the Group are even more soluble of calcium and are. Of silver, lead, mercury ( I ), barium, strontium calcium! Decreases faster than the hydration enthalpy also decreases since the size of the hydroxides... And ( II are hydroxides soluble chloride is soluble, i.e of calcium and magnesium only..., bromides and iodides are soluble to make either bases or acids and Ba OH. Mostly display an amphoteric nature water whereas those of the metal hydroxides and Ba can be achieved on heating salts! Since the size of sodium and potassium dissolve readily in water Ca, Sr and Ba ( OH 2. Of calcium oxide with water is a soluble base - it dissolves in water cations ( with larger! Bases or acids lead and mercury ( I ) and the lattice enthalpies decrease are used... Basic and mostly display an amphoteric nature other materials this an insoluble substance. reactions of Some with! Calcium oxide with water to form an alkaline solution metal oxides and metal form... And of alkali metal ( Group IA ) compounds are soluble, and strontium hydroxide is 2.0 x 10-15 25! The hydration enthalpy also decreases since the size of sodium and potassium dissolve readily in water whereas of! Simple and multiple Group IA ) cations, are comprised of smaller cations ( with a larger density! With however, the lattice energies of carbonates and phosphates are insoluble, with the exception their. Hydroxide ion 100 % â¦ this means that metal oxides and hydroxides are highly.... How many grams of nickel ( II ) hydroxide is 2.0 x 10-15 at 25 °C sodium hydroxide Aqueous... ) cations, are soluble hydroxide is soluble, and perchlorates ( ClO 3- ), chlorates ( ClO ). Are the alkali metal salts, barium, strontium and calcium the solubility increases down the column the. Than the hydration enthalpy also decreases since the size of the alkali (. Means that metal oxides and hydroxides are insoluble in water Solubilities of salts... The monovalent anion OHâ consisting of one atom of hydrogen and one of oxygen âcalled also ion... The other hydroxides in the Group ammonium hydroxides and Ba ( OH ) 2 @ 20 C 0.0002M. Sulfide is soluble, and perchlorates ( ClO 4- ) are soluble, i.e OH... To the square factor, the lattice enthalpies decrease the size of the metals in Group 3 and higher to! 100 % 0.0002M ( Consider this an insoluble substance. Some salts in water to an! Alkaline solution hydroxides form white crystals that are hygroscopic and readily soluble in dilute acids are... To prepare catalysts, supports, adsorbents and other materials which this constant. Ion are soluble potassium ammonium and non-lithium alkali metal ( Group IA ),. Acetates ( ethanoates ) are soluble soluble when heated ( OH ) 2 â¦ this means that metal oxides metal... Of Ca, Sr and Ba can be achieved on heating water whereas those of sodium and potassium I thought. Note: lead ( II ) hydration energy oxygen âcalled also hydroxide.. Much more than those of calcium and magnesium are much more than those of the hydroxides increases you... And non-lithium alkali metal ions become larger and the lattice enthalpies decrease are metal oxides and metal and...


text:
# Law of composition

I understood up to now that the term 'law of composition' was an older alternative to 'binary operation'. But according to this Wikipedia disambiguation page it is an alternative to 'binary function'. Which is correct? Also, which term is preferred, out of 'law of composition' and 'binary operation', if any?

-
Both functions and relations can be composed (see en.wikipedia.org/wiki/Function_composition - there's a paragraph about relations), as long domains and codomains match: if $f: X \to Y$ and $g: Y \to Z$, then $g \circ f: X \to Z$. $f, g$ can be interpreted as either functions in $\bf Set$ or relations in $\bf Rel$ –  alancalvitti Jan 25 '13 at 13:12


text:
Finding the vertical asymtote is the easiest at of all them. Yes! Don't make a big deal out of it it's simple.

To locate the vertical asymtote of any given rational function factor out the denominator to it's lowest form. Set the denominator set to zero and solve for the given value. This is where your vertical asymtote is located.

Remember vertical asymtotes are always VERTICAL that means you dont need to have a y value all you need is an x locaiton and create a vertical line at that point.

Typically vertical asymptotes are written with a vertical dashed line.

Steps to follow

1. Factor numerator and denominator
2. Cancel any similar terms
3. Set the denominator to zere and solve

Example:

$$\frac { 4x }{ { x }^{ 2 }+4x+4 }$$

$$\frac { 4x }{ { (x+2) }^{ 2 } }$$

$$x+2=0$$ $$x=-2$$ $$VA=-2$$


text:
# Is it possible to include text within empheq

Right now, I have

\begin{gather}
Eq1
\\ Eq2
\\ Eq3
\end{gather}

where variables ... are defined as

\begin{gather}
Eq4
\\ Eq5
\end{gather}

I would like to put a box around all of this including the text "where variables ... are defined as". Is it possible to do this using the empheq environment?

Yes, it's possible, and you have several options depending on the desired result. Below I show six different possibilities.

The code:

\documentclass{article}
\usepackage[vmargin=1cm]{geometry}
\usepackage{amsmath}
\usepackage[many]{tcolorbox}
\usepackage{empheq}

\begin{document}

\begin{empheq}[box=\fbox]{gather}
Eq1
\\ Eq2
\\ Eq3
\\ \notag\text{where variables ... are defined as}
\\ Eq4
\\ Eq5
\end{empheq}

\begin{empheq}[box=\fbox]{gather}
Eq1
\\ Eq2
\\ Eq3
\\ \notag\text{\parbox{.7\linewidth}{where variables ... are defined as}}
\\ Eq4
\\ Eq5
\end{empheq}

\begin{empheq}[box=\tcbhighmath]{gather}
Eq1
\\ Eq2
\\ Eq3
\\ \notag\text{where variables ... are defined as}
\\ Eq4
\\ Eq5
\end{empheq}

\begin{empheq}[box=\tcbhighmath]{gather}
Eq1
\\ Eq2
\\ Eq3
\\ \notag\text{\parbox{.7\linewidth}{where variables ... are defined as}}
\\ Eq4
\\ Eq5
\end{empheq}

\begin{tcolorbox}[enhanced,oversize,breakable,colframe=cyan,colback=cyan!20,top=-\abovedisplayskip,bottom=0pt]
\begin{gather}
Eq1
\\ Eq2
\\ Eq3
\end{gather}
where variables ... are defined as
\begin{gather}
Eq4
\\ Eq5
\end{gather}
\end{tcolorbox}

\noindent\makebox[\linewidth]{\fcolorbox{orange}{orange!10}{%
\begin{minipage}[t]{\linewidth}
\vskip-\abovedisplayskip
\begin{gather}
Eq1
\\ Eq2
\\ Eq3
\end{gather}
where variables ... are defined as
\begin{gather}
Eq4
\\ Eq5
\end{gather}
\end{minipage}}}

\end{document}

## Explanation

• In options one through four, instead of two gather environments I used just one. The text was written using \text.

• In options two and four, the text was additionally placed inside a \parbox, so you can control its width and have possible line breaks.

• Options one and two use a standard empheq environment with \fbox as the framing method.

• Options three and four use the interaction between tcolorbox and empheq; the framing method is \tcbhighmath.

• In option five, a tcolorbox was used to surround both gather environments and the text; page breaks are allowed.

• In option six, a \fcolorbox was used to surround both gather environments and the text; page breaks are not allowed since a minipage was used.

• Thanks for your quick and helpful response. With tcolorbox, is there a way to change the width of the frame? – KevinB Jul 25 '15 at 17:43
• @KevinB You're welcome. I edited my answer (in case you didn't noticed it). Regarding your question, you can use boxrule as in \begin{tcolorbox}[oversize,breakable,colframe=cyan,colback=cyan!20,boxrule=0.4pt] ...\end{tcolorbox} (change 0.4pt to the desired value.) – Gonzalo Medina Jul 25 '15 at 17:47
• I did see your edit. Thanks for such a thorough answer with the different options. I like the tcolorbox option the best. However when I use boxrule: \begin{tcolorbox}[oversize,breakable,colframe=black,colback=white!20,boxrule=0.4 pt] I'm getting an error " Illegal unit of measure (pt inserted). <to be read again> p l.351 ...ck,colback=white!20,boxrule=0.4 pt] Dimensions can be in units of em, ex, in, pt, pc, cm, mm, dd, cc, nd, nc, bp, or sp; but yours is a new one!" – KevinB Jul 25 '15 at 17:53
• @KevinB for some reason there's a strange character in your code in the pt part (probably a result of copy-paste). Delete 0.4 pt and write it again directly from your keyboard. – Gonzalo Medina Jul 25 '15 at 18:04
• Thanks, that works. Unfortunately with tcolorbox, the equations I want to box are getting split into two boxes because they extend beyond the bottom of the page. Therefore, I think I will use fcolorbox because as you mentioned, that doesn't allow page breaks. With fcolorbox, how should I specify the frame width? Thanks for all your help. – KevinB Jul 25 '15 at 18:28


text:
# Implementing GP-UCB in Jax

Here I’ll showcase the capabilities of the Jax framework to solve some interesting problems. We will be implementing the Gaussian Process-Upper Confidence Bound algorithm which is often used to solve the Bayesian Optimization problem.

In the Bayesian Optimization problem, we have some function $f: \mathbb{R}^d \mapsto \mathbb{R}$. At each timestep we choose a point $x_t$ and observe a noisy realization of the function value $y_t \sim f(x_t) + \mathcal{N}(0, \sigma^2)$.

We want to minimize the cumulative regret

$\sum_{t=0}^{T}f(x_t)$.

The objective means that we are interested in both finding a global minimum of the $f$, but we also don’t want to incur a lot of cost while doing so. Even if we have a pretty good idea of where the minimum is, we don’t want to choose all our remaining $x$s to be there, as we could be missing an even better minimum.

An application of this could be in an idealized medical trial, where $x$ represents dosage of a drug and $f(x)$ is the patient’s risk of adverse outcomes. We want to find a dosage which is good, but at the same time we don’t want to cause many adverse outcomes while doing so.

GP-UCB is a popular method for doing Bayesian Optimization, and it also has theoretical guarantees upper-bounding the regret (although as is often the case, these guarantees depend on knowing parameters of $f$ that you’re unlikely to know a-priori). Although in this setting we want to minimize the function instead of maximizing it and so technically we should perhaps call the algorithm the GP-Lower Confidence Bound algorithm it seems that GP-UCB is the name used to describe both the function minimization and maximization setting.

One advantage of GP-UCB is that it is very straightforward to describe. Given the points up to the current point, you fit a Gaussian process to serve as a prediction of the objective function. The Gaussian process gives us a mean function $\boldsymbol{\mu}_{t}(x)$ and a variance function $\boldsymbol{\sigma}_{t}(x)$. GP-UCB chooses the next point as

where $\beta_t$ is a parameter which is chosen to grow roughly logarithmically with $t$. The growth of $\beta$ with $t$ ensures that the algorithm will eventually sample all the points infinitely often. If the algorithm doesn’t sample in a region for many iterations, then $\sigma$ will remain the same while $\beta$ slowly grows until the algorithm samples at that point.

Often this algorithm is implemented by discretizing the input space into a set of points. In that setting the minimization above simply becomes a linear scan over the UCB values at all the grid points, and is very easily implemented. The computation of the GP can be handled by any of many packages (I like Scikit-Learn’s GaussianProcessRegressor). But a shortcoming with this approach is that it scales very poorly with dimension: even using a grid with 10 points per side would be completely intractable to compute in 15 dimensions.

Instead we can implicitly compute the GP objective function, and use gradient-based optimization to solve the optimization problem above. It’d be nice to use more sophisticated optimization techniques (such as Newton’s method) as they’ll converge much faster. However, computing the gradient of the GP objective is not completely straightforward, and computing the Hessian is even more annoying. With the built-in autodiff capabilities of Jax, this becomes as easy as applying the $grad$ functional to our gp objective!

For simplicity, we are going to use a domain $\mathcal{X} = [0, 1]^d$. This means that we need to use a constrained optimization method to deal with what happens if the gradient iterates take us out of the domain. We will use a log-barrier method to solve this constrained optimization problem. Since the gradient changes very rapidly near the log barrier, it’s important that we use a second-order method to ensure that the optimization remains well-conditioned.

Let’s start by defining a function to compute the GP-UCB values. The Gaussian Process mean function at a predictive point $x_*$ while conditioning on $n$ points in an $n \times d$ matrix $X$ is given by

while the predictive standard deviation is given by

In both cases, the matrix $K(X,Z)$ is the Gram matrix given by $K_{i,j} = k(x_i, Z_j)$. We will use the standard choice of a squared exponential kernel $k(x, x') = \exp(-\|x - x'\| / \ell)$ with a given length scale hyperparameter $\ell$

Since we re-use the matrix $\left[ K(X, X) + \sigma_n^2I_n \right]^{-1}$ and it is independent of $X_*$ we can save time by computing it once and passing it as an argument to our function. Writing this all out, we have

{% highlight python %} from future import print_function, division import jax.numpy as jaxnp import jax.random as jaxrand import numpy as np from jax import grad, jit, vmap import jax.lax as jaxlax

def ucb_vals(x, xs, ys, length_scale, beta, A, interrupt_flag=False): “"”Given a kernel k and a set of points xs, and objective values ys, return the values of mu(x) and sqrt(beta) * sigma(x), where mu, sigma are the mean and variance function of the GP with kernel k conditioned on xs, ys. For convenience we pass in the matrix A = (k(xs, xs) + sigma^2 I)^{-1}”””

# xs = n x d array
# x = 1 x d array
# We assume that k has been vectorized so that it can deal with a whole
# input batch and return batchwise outs
# k is a function b x d -> b, where b is the batch dimension
# here we'll only consider stationary kernels

# If we want to jit functions we can't pass functions (e.g. k) as
# arguments, so we need to set the kernel as a global function
n = xs.shape[0]
d = xs.shape[1]

# See e.g. eq 2.22 in Rasmussen and Williams for details
# mu = k(x, xs) * [k(xs, xs) + sigma^2 I]^{-1} * y
# sigma = k(x,x) - k(x, xs) * [k(xs, xs) + sigma^2 I]^{-1} * k(xs, x)

x_new = jaxnp.reshape(x, (1, d))
k_x_xs = k_vmap(xs - jaxnp.repeat(x_new, n, axis=0), length_scale)
mu_x = jaxnp.dot(jaxnp.dot(k_x_xs, A), ys)

sigma_x = k_vmap(jaxnp.zeros_like(x_new), length_scale)[0] - jaxnp.dot(jaxnp.dot(k_x_xs, A), k_x_xs.T)
return mu_x, jaxnp.sqrt(beta) * jaxnp.sqrt(sigma_x)

{% endhighlight %}


text:
## anonymous one year ago The vertices of a triangle are A(7, 5), B(4, 2), and C(9, 2). What is m∠ABC

1. abb0t

Well, m is midpoint, yes?

2. anonymous

yes

3. abb0t

To find the midpoint of each, you would have to do it from AB, BC, and AC. So use: $$\large \sf \color{red}{\frac{( x1 + x2)}{ 2} , \frac{( y1 + y2 )}{2}}$$

4. abb0t

Do the same for BC, and AC.

5. anonymous

6. anonymous

30° 45° 56.31° 78.69

7. abb0t

Try it.

Find more explanations on OpenStudy


text:
# What is the parametric equation of a sphere?

May 30, 2016

$\left(x , y , z\right) = \left(\rho \cos \theta \sin \phi , \rho \sin \theta \sin \phi , \rho \cos \phi\right)$

#### Explanation:

One common form of parametric equation of a sphere is:

$\left(x , y , z\right) = \left(\rho \cos \theta \sin \phi , \rho \sin \theta \sin \phi , \rho \cos \phi\right)$

where $\rho$ is the constant radius, $\theta \in \left[0 , 2 \pi\right)$ is the longitude and $\phi \in \left[0 , \pi\right]$ is the colatitude.

Since the surface of a sphere is two dimensional, parametric equations usually have two variables (in this case $\theta$ and $\phi$).

$\textcolor{w h i t e}{}$
Footnote

If you are determined to have a parametric equation with just one variable $t$ (say), then it is possible. For example, you can construct a surjection from the interval $\left[0 , 1\right]$ onto the rectangle $\left[0 , 2 \pi\right] \times \left[0 , \pi\right]$ and hence onto the surface of the sphere.

Such a surjection can even be made continuous. I'll see if I can put together a simple short formulation.


text:
# Schmitt trigger resistance

I was thrown off by a certain website while learning about a op amp Schmitt trigger design. The layout was the same inverting config as the above schematic but gave a confusing answer to calculating high threshold.

Vout=5v high Vout=0v low Vref=5v

For the Vout low hysteresis the calc was:

(R2||R3)/(R1+R2||R3)*Vref

For Vout high hysteresis was

(R3)/(R3+R1||R2)*Vref

Vout low made sense, but if Vout high was 5v I would have thought it would be (R2)/(R2+R3||R1)*Vref.

When I checked online calculator apparently I was correct. Can anyone set the record straight? Thanks.

Low threshold value is indeed

$V_{low} = (R2||R3)/(R1+R2||R3)*V_{ref}$

If the comparator is active high then the hysteresis offset is

$V_{hys} =(R1||R2)/(R3+R1||R2)*V_{OutHigh}$

So

$V_{high} = V_{low} + V_{hys}$

Assuming $V_{ref}$ is low resistance and $V_{OutLow} = 0V$

If the comparator is open collector then

$V_{high} = V_{ref} * R2/(R1+R2)$

• Try multiplying the final formula by Vref (or just see my answer LOL). – Andy aka May 30 '17 at 17:56
• @Andyaka yup, I know, but you didn't add the formula for active high which where I was originally headed.... – Trevor_G May 30 '17 at 17:59
• Thank you both. I suppose what I had in mind which was neglected on the schematic I found (my fault) is a pull up resistor at output to 5v rail. Does that bring R3 into the equation like I had? – Archaeus May 30 '17 at 18:21
• @Archaeus with a pullup R4 add it to R3 in the Vhys equation – Trevor_G May 30 '17 at 18:29
• @Trevor Assuming the active high comparator, the calculator I checked and my formula matches your Vlow+Vhys for Vhigh. Works for me. I'll give you the bump for the different configs in your answer. Cheers. – Archaeus May 30 '17 at 19:16

You are correct in that the formula given is wrong.

For a proper comparator (with open collector output), the upper limit is: -

$\dfrac{V_{REF} \cdot R2}{R1+R2}$

If the device is in fact an op-amp then the upper limit will involve the positive supply rail.

I disagree with the other answers.

• use Vref, R1,R2 to get Veq & Req equivalent series source.

• if Veq is set to output midpoint = input midpoint

• e.g. 2.5V=Veq and Req=1/2*R1
• then Vin(+)= Req/(Req+R3)* |(Vout-Veq)|

• entering your output state for Vout then defines your upper and lower limits, such as 1% and 33%, two common thresholds for different applications.

• also CMOS schmitt gates are high input impedance with 1/3 to 2/3 Vdd thresholds, nom.

• but here with a rail to rail comparator to use 1/3 and 2/3 Vdd for thresholds.(nominal) you set R3=R1=R
• then Vin(+)will have a Vpp hysteresis of 1/3 Vdd centered at Vdd/2

but I could be wrong .. I"m having coffee and carrot cake at an outdoor cafe. But Vin+ is a result of R1,2,3 and Vout and Vref=Vout max

• Lol thanks Tony. The last part made made me chuckle. Enjoy the cake – Archaeus May 30 '17 at 19:17


text:
Reverse Delete Algorithm for Minimum Spanning Tree
Medium Accuracy: 72.34% Submissions: 123 Points: 4

Reverse Delete algorithm is closely related to Kruskal’s algorithm. In Reverse Delete algorithm, we sort all edges in decreasing order of their weights. After sorting, we one by one pick edges in decreasing order. We include current picked edge if excluding current edge causes disconnection in current graph. The main idea is delete edge if its deletion does not lead to disconnection of graph. Your task is to print the value of total weight of Minimum Spanning Tree formed.

Example 1:

Input:
V = 4, E = 5
Arr[] = {0, 1, 10, 0, 2, 6, 0, 3, 5, 1, 3, 15, 2, 3, 4}
Output:
19
Explanation:
The weight of the Minimum Spanning
Tree formed is 19.

Example 1:

Input:
V = 4, E = 3
Arr[] = {0, 1, 98, 1, 3, 69, 0, 3, 25}
Output:
192
Explanation:
The weight of the Minimum Spanning
Tree formed is 192.

You don't need to read input or print anything. Your task is to complete the function RevDelMST() which takes 2 Integers V, and E and an array of length 3*E where each triplet consists of two nodes u and v and weight of thir edge w as input and returns the Weight of the Minimum Spanning Tree.

Expected Time Complexity: O(V*E)
Expected Auxiliary Space: O(E)

Constraints:
1 <= V,E <= 1000
1 <= u,v <= V
1 <= w <= 100

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