What is the indefinite integral of cos^2x?

List Trigonmetric identities which could help to simpilfy integral

Use cos(2x)= Cos²x-sin²x and sin²x=1-cos²x

Sub identity 2 into 1 and rearrange to show Cos²x=(1+cos2x)/2

and integrate to find the answer is x/2 + sin(2x)/4 + c