`inttan^(4)xdx`

Explanation

`inttan^(4)xdx`
`=int tan^(2)x.tan^(2)xdx`
`=int tan^(2)x.(sec^(2)x-1)dx`
`=int tan^(2)x.sec^(2)xdx" माना "tanx=t`
`" "-int tan^(2)x dx" "rArr sec^(2)x dx=dt`
`=intt^(2)dt-int(sec^(2)x-1)dx`
`=(1)/(3)t^(3)-tanx+x+c`
`=(1)/(3)tan^(3)x-tanx+x+c`