Question

Find the exact real value of arccos ( √2/2)

Answer 1

The arccos function takes as its "input" a real number, and returns as its "output", the angle that lies between 0 and \(\pi\) (in radians) that has THAT NUMBER as it's cosine value.

So do you recognize √2/2 as the cosine value for a particular angle that you are familiar with from the unit circle?