# 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.