Hi there any help showing the below integral equals the function +C?
integral= sqrt[(a^2-x^2]dx
function=(a^2/2)(theta+sin(theta)cos(theta))+c
using Substitution x=(a)sin(theta).
tried using
integral dx/sqrt[(a^2-x^2]=theta + C but can't seem to crunch it!
used dx=acos(theta).
any help appreciated.