∫π/6π/311+tan3xdx=
π12
π4
π3
π6
∫π/6π/311+Tan3xdx=∫π/6π/3Cos3xCos3x+Sin3xdx since∫abfxfx+fa+b-xdx =b-a2
=b−a2
=π3−π62
=π12