How to type answers: use
x^2, x/2, sin(x), cos(2x), ln(x), e^x, atan(x) (for tan-1), asin(x), sqrt(x). Use * between terms if a product isn't accepted (e.g. x*e^x). Any algebraically equivalent answer is marked correct. The +C is optional, except on questions that give a starting value: there, don't add +C.