`intsin^3xsec^14xdx`

Explanation

`intsin^3xsec^14xdx`
=`intsin^3x/cos^14x dx`
=`int((1-cos^2x)sinx)/cos^14x dx`
[Put cosx=t
Then sinxdx=-dt]
=`int(t^2-1)/t^14 dt=int(t^-12-t^-14)dt`
=`-1/11t^-11+1/13t^-13+C`
=`1/13sec^13x-1/11sec^11x+C`