Question 601011
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Represent *[tex \Large -15^\circ] as *[tex \Large \frac{-30^\circ}{2}]


Recall that *[tex \Large 30^\circ\ =\ \frac{\pi}{6}] radians, *[tex \Large \sin(-\varphi)\ =\ -\sin(\varphi)], *[tex \Large \cos(-\varphi)\ =\ \cos(\varphi)], *[tex \Large \sin\left(\frac{\pi}{6}\right)\ =\ \frac{1}{2}], *[tex \Large \cos\left(\frac{\pi}{6}\right)\ =\ \frac{\sqrt{3}}{2}].


Now use


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \tan\left(\frac{\varphi}{2}\right)\ =\ \frac{\sin(\varphi)}{1\ +\ \cos(\varphi)}]


to calculate the desired function value.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
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