Question

How do you simplify `cos^-1 (-1/2)`?

Answer 1

See Below.

Explanation:

Let's assume `x = cos^-1(-1/2)`

So, According to the Definition,

`color(white)(xx) cos x = -1/2`

`rArr x = (2pi)/3 +- 2npi, (4pi)/3 +- 2npi`

For First Revolution, The Values for `x` are `(2pi)/3` and `(4pi)/3`, then use the period to find the full set of solutions.

Hope this helps.