Question

How do you find the exact value of `cos^-1 (-sqrt3/2)`?

Answer 1

`cos^(-1)(-sqrt3/2)=+-(5pi)/6`

Explanation:

As `cos((5pi)/6)=-sqrt3/2` and also `cos(-(5pi)/6)=-sqrt3/2`. Hence

`cos^(-1)(-sqrt3/2)=+-(5pi)/6`