Need help with practice problem!

1. As one might expect, the volume of a four dimensional object can be found with a quadruple integral. Suppose that H is a solid in four space. Also suppose that the solid H is bounded above by w= g, (x, y, z) and below by w= g, (x, y, z). The volume of H is given by: 82 ( x, y , = ) dw dV where D = (x, y, z) : there exists w so that (x, y, z, W) E H) . One can D 81 (x, y,=) continually generalize this idea to find volumes of n-dimensional solids. The following question requires one to use a quadruple integral. The four dimensional unit ball is the set of points: BA = (x, y, z, w) : x + y + z +was1. Find (with proof) the exact volume of BA