How this equation is working?

Now by using MAPLE to evaluate the value of above integral is as below; 2 x 27 3 . sin(t) . sin(t) . sin (t) . cos(t) + 2. cos(t)-cos(t) . cos(t) . cos(t) dt O Hence, the value of Flux of F = (x2 + y' )i +2xyj across the curve is 0