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Given an angle, in degrees, how can I get the trigonometric circle point coordinates for it?

For instance, given the angle 0, I would get (1,0). 90 would be (0,-1). Clockwise.

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2 Answers 2

up vote 2 down vote accepted

Does $x=\cos \theta , y=-\sin \theta (\theta\ \ $ in degrees) meet your need? It looks like you are measuring angles clockwise while the mathematical standard is counterclockwise.

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The coordinates are $(\text{Cos}\, \theta, -\text{Sin}\,\theta)$. Here by $\text{Cos}$ and $\text{Sin}$ we mean the functions that take input in degrees and evaluate the cosine and sine. So these are the standard calculator cos and sin when the calculator is in degree mode.

The usual thing is to move counterclockwise, in which case the answer is $(\text{Cos}\, \theta, \text{Sin}\,\theta)$. We switched to clockwise by first using the angle $360 -\theta$ (well, to tell the truth, $-\theta$), and then simplifying.

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