Evaluate the following:
`intx^2e^(ax)dx`

Explanation

`intx^2e^(ax)dx` [Choose `x^2` as first and `e^(ax)`
as second function]
=`x^2.e^(ax)/a-int2x.e^(ax)/a dx`
=`1/a x^2e^(ax)-2/a{x.e^(ax)/a-int1.e^(ax)/a dx}`
=`1/ax^2e^(ax)-2/a^2 xe^(ax)+2/a^3.e^(ax)+C`