Volume engendré par une courbe

f(x) = If[-1 ≤ x ≤ 0, sqrt(1 - x^(2))]
g(x) = If[0 ≤ x ≤ 1.5707963267948966, cos(x)]
a = 360 (slider from 0 to 360, step 1)
f_{1} = Rotate(f, a°, xAxis)
g_{1} = Rotate(g, a°, xAxis)