what is the problem with that integral ? [closed]

edit

I try to integrate this:

sage: integrate(integrate(integrate(2cos(z)sin(atan((2cos(y)-0.5+x)/(2sin(y)))),y,0,pi/2),x,0,1),z,0,pi/2);

There is a problem :

"ECL says: In function ZEROP, the value of the only argument is ((RAT SIMP) -0.5 1.0) which is not of the expected type NUMBER"

Could you help me please ?