How and why?

Question

Could somebody explain how I am supposed to get (1/3)*(x^2-8)*sqrt(x^2+4) for an antiderivitive of the integral int( x^3/sqrt(x^2+4) dx ? What would be the best way to go about solving this problem? I know that i could sepurate it into products so that I can integrate by parts, but I could also use u-substitutions? Should I use trig substitutions if that would make it easier because x^2+4 is of the for where I should use sin(theta) substitution? What is the best way to go about this problem and ones like it?

sorry i reposted this one in the math because i forgot to post it in the right one

Answer 1

Best Way.... Stick it in the Math Category...