Question 333374
<font face="Garamond" size="+2">


Use the Unit Circle:


<img src="http://www.math.ucsd.edu/~jarmel/math4c/Unit_Circle_Angles.png">


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \frac{-9\pi}{4}\ =\ -2\pi\ -\ \frac{\pi}{4}]


Once around the circle clockwise and then another *[tex \LARGE \frac{\pi}{4}]


That puts you at *[tex \LARGE \frac{7\pi}{4}].  *[tex \LARGE \cos(\varphi)] is the *[tex \LARGE x]-coordinate, *[tex \LARGE \sin(\varphi)] is the *[tex \LARGE y]-coordinate, and *[tex \LARGE \tan(\varphi)] is the *[tex \LARGE \frac{\cos(\varphi)}{\sin(\varphi)}]









John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
</font>