The exact command I'm using is

simplify(int(int(sin(v)*sqrt(cos(t)^2+4*sin(v)*sin(t)*cos(v)*cos(t)*sin(w)
                      +4*cos(v)^2-cos(w)^2*cos(t)^2
                      +cos(t)^2*cos(v)^2*cos(w)^2-5*cos(t)^2*cos(v)^2),
                      v=0..1/2*Pi),w=0..2*Pi);

I have to get an expression out whit t in it :) But thanks for the tip about evalf

I have to get an expression out whit t in it :) But thanks for the tip about evalf