Evaluate: `intx^2tan^(-1)x\ dx`

Explanation

Given integral is,
`intx^2tan^(-1)x\ dx`
`=x^3/3 tan^-1 x-int1/(1+x^2)xxx^3/3 dx`
`=tan^-1x(x^3/3)-1/3intx^3/(1+x^2)dx`
taking `1+x^2=t`
`=>2dx=dt`
`=>dx=(dt)/(2x)`
putting these values,given integral becomes
`tan^-1(x^3/3)-1/3intx^3/t dt`
`=tan^-1(x^3/3)-1/6(1+x^2-log|1+x^2|+c)`