# Determine the quadratic function whose graph is given

Printable View

• January 8th 2013, 10:11 PM
alex95
Determine the quadratic function whose graph is given
Hi All,

I would really appreciate some help/hints for the following problem I am stuck on.
Determine the quadratic function whose graph is given:
The function has given points at (-1,5), (3,5), and y-intercept at (0,-1)

I know that the axis of symmetry (h) is at 1 because it is the mid-point between -1 and 3. If I plug that into the function a(x-h)^2 + k, I still have two unknowns, a and k
a(x-1)^2+k
Can someone please explain to me how to solve this. Thank you very much in advance.

Alex
• January 8th 2013, 10:21 PM
MarkFL
Re: Determine the quadratic function whose graph is given
Let:

$f(x)=ax^2+bx+c$ and use the given points to state:

$f(-1)=5$

$f(0)=-1$

$f(3)=5$

The second equation tells you $c=-1$, and this along with the first and third equations will give you two equations and two unknowns.
All times are GMT -8. The time now is 09:52 AM.
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 5, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "github"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "english_confidence": 0.9464515447616577, "perplexity_flag": "middle"}