V=∫−aa∫−a2−z2a2−z2∫x2+z2a2dydxdzV = \int_{-a}^a\int_{-\sqrt{a^2-z^2}}^{\sqrt{a^2-z^2}}\int_{\sqrt{x^2+z^2}}^{a^2}dydxdzV=∫−aa∫−a2−z2a2−z2∫x2+z2a2dydxdz