Originally Posted by

**ZaZu** Hello,

A question says solve $\displaystyle sin(x)=-sqrt(3)/2$ with no definite domain

Now I know how simple this is ..

But in class the teacher started explaining some weird stuff I couldnt understand.

Anyway, I know that I do : $\displaystyle arcsin(-sqrt(3)/2)$

ill get $\displaystyle x=-60$

now arent I supposed to do the following ? :

$\displaystyle

180-(-60)= 240$

So the solutions are $\displaystyle -60 +2(pi)n ; n= +/- 1 +/- 2 +/- 3 ....$

and $\displaystyle 240 +2(pi)n ; n= +/- 1 +/- 2 +/- 3 ....$

Is the answer correct ? or am I doing something wrong :S

My teacher presented positive answers (+60) and not -60..

and in Wolfram Alpha, the answers are 120 and 60 ..

Please explain why

Thanks !!