Given that:
=∫6sin3x+5cos3xsin2xcos2xdx
=∫6sinxcos2xdx+∫5cosxsin2xdx
=∫6tanxsecxdx+∫5cotxcscxdx
[∵∫tanxsecx=secx,∫cotxcscxdx=−cscx]
=6secx+5(−cscx)+constant
=6secx−5cscx+constant