Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

More specifically, how would you write $\csc(-2\pi/5)$ as the trigonometric function of a positive number?

share|improve this question
1  
sine (and hence cosecant) is an odd function. Basically, you can take the negative outside. –  The Chaz 2.0 Apr 25 '12 at 1:42
    
Just to clarify what Chaz is saying, $$\sin(-x) = -\sin x$$ from where the same holds for the cosecant. –  Pedro Tamaroff Apr 25 '12 at 1:47

1 Answer 1

up vote 1 down vote accepted

Hint: Recall that $\sin(x)=\sin(x+2k\pi)$ for any integer $k$. Let $x=-2\pi/5$ and let $k=1$.

share|improve this answer
    
This might be more in line with the desired solution than my comment above, but who knows! "This answer is useful" –  The Chaz 2.0 Apr 25 '12 at 2:20

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.