Question

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

Answer 1

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

`sintheta=-1/2`

`theta=210º` and `theta=330º`

if `0< theta<= 360`