Question

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

Answer 1

`cos^(-1)(1/2)=2npi+-pi/3` where `n` is an integer.

Explanation:

We know that `cos(pi/3)=1/2`, however as

`cos(-theta)=costheta`, we also have `cos(-pi/3)=1/2`

Further function cosine has a periodicity of `2pi`

hence `cos^(-1)(1/2)=2npi+-pi/3` where `n` is an integer.