The Tangent Function, Reciprocal Trig Functions, and Extra Credit

Remember how I said that if you memorize the coordinates of the terminal points for the special angles, you can evaluate any trig function value for a special angle? That’s because all trig functions can be expressed in terms of sine and cosine:

\tan=\frac{\sin}{\cos}

\cot=\frac{\cos}{\sin}

\csc=\frac{1}{\sin}

\sec=\frac{1}{\cos}

EXTRA CREDIT: Prove any of these equations geometrically.

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