Evaluate: `intx^3log2x\ dx`

Explanation

Let `I=intx^3log2x\ dx`
taking `u=log2x`
`=>u'=1/x`
and `v'=x^3`
`=>v=x^4/4`
so,
`I= log 2x xx x^4/4-int1/x xx x^4/4 dx`
`=log 2x x^4/4- int x^3/4 dx`
`=(x^4log 2x)/4-x^4/16+c`