Calculate an angle from Tan, Cos, or Sine

I'd like to calculate an angle using nothing but either tangent, cosine, or sine, or any combination of the two. Is this possible? If so, how?

I know how to program, but I find that I can't really get much farther until I start learning higher level mathematics. Therefore, I'm writing out C functions to teach me maths :D.

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So this is for programming? You'll want to look into two-argument arctangent (`atan2()` in some languages). – J. M. Dec 24 '11 at 8:44

2 Answers

You want to learn programming and advanced mathematics then find root of $$f(\phi) = \cos\theta - \cos \phi$$

using Bisection method or Newton-Raphson method. Writing program for any of the methods is easy.

Note: Here $\cos \theta$ is value of cosine given to you and $\phi$ is your guess.

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Inverse Trigonometric Functions - Wikipedia

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Providing me with a link isn't going to help much - I already looked through that before asking here. There is tons to read, and for you (as a contributor) to post only that seems...well, lacking if I do say so myself. – about blank Dec 25 '11 at 6:26
@Holland I interpreted your question as "Given the sine,cosine, or tangent of an angle, how do I find the angle?", which my link answers in far more depth than any answer I could ever give. I'm sorry if that link isn't helpful to you, but you gave me very little to go on in your question, so I had to do the best I could. In the future, you should provide more detail about what you've looked at and where you're stuck. That way, we can give better answers, and also know that you've done the obligatory google search that surprisingly many askers here neglect to do. – Alex Becker Dec 25 '11 at 6:35

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Understandable. I'll be sure to note that the next time I ask a question. – about blank Dec 25 '11 at 6:56
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