Calculate . The answer may contain roots but not trigonometric functions.

im really bad on the geometry so any1 give me tips?

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- Sep 25th 2012, 05:38 AM #1

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- Sep 25th 2012, 05:48 AM #2

- Sep 25th 2012, 06:01 AM #3

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- Sep 25th 2012, 06:11 AM #4

- Sep 25th 2012, 06:24 AM #5

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- Sep 25th 2012, 06:29 AM #6

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- Sep 25th 2012, 06:33 AM #7
## Re: cot

$\displaystyle \cot(x)=\frac{\cos(x)}{\sin(x)}$

You should know (or be able to quickly find using the unit circle):

$\displaystyle \cos\left(\frac{5\pi}{6} \right)=-\frac{\sqrt{3}}{2}$

$\displaystyle \sin\left(\frac{5\pi}{6} \right)=\frac{1}{2}$

If you prefer to use a first quadrant angle, then you may write:

$\displaystyle \cot\left(-\frac{31\pi}{6} \right)=-\cot\left(\frac{31\pi}{6}-5\pi \right)=-\cot\left(\frac{\pi}{6} \right)$

- Sep 25th 2012, 06:37 AM #8