Question 597188
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Typing in all caps is shouting.  It is both rude and annoying.  I don't want an apology or an excuse; just stop doing it.


*[tex \LARGE  \frac{4\pi}{3}] is in QIII where both sine and cosine are negative.


Use the unit circle to find *[tex \LARGE \sin\left(\frac{4\pi}{3}\right)] and *[tex \LARGE \cos\left(\frac{4\pi}{3}\right)]


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


*[tex \LARGE \cos] is the *[tex \LARGE x] value and *[tex \LARGE \sin] is the *[tex \LARGE y] value.


*[tex \LARGE \tan(\varphi)\ =\ \frac{\sin(\varphi)}{\cos(\varphi)}]


Cotangent is the reciprocal of tangent.  Secant is the reciprocal of cosine.  Cosecant is the reciprocal of sine.  Don't forget to rationalize all denominators.


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