# How do you evaluate sin^-1(-1/2) without a calculator?

Dec 5, 2016

The answer is S={210º,330º}

#### Explanation:

We know that sin30º=1/2

So, we are looking for a solution in the 3rd and 4th quadrant

$\sin \theta = - \frac{1}{2}$

theta=210º and theta=330º

if $0 < \theta \le 360$