a. ∫04∫0r2−x2∫0r2−x2−y2dzdydx\displaystyle\int_0^4\int_0^{\sqrt{r^2-x^2}}\int_0^{\sqrt{r^2-x^2-y^2}}dzdydx∫04∫0r2−x2∫0r2−x2−y2dzdydx b. ∫02∫0r2−y2∫0r2−x2−y2dzdxdy\displaystyle\int_0^2\int_0^{\sqrt{r^2-y^2}}\int_0^{\sqrt{r^2-x^2-y^2}}dzdxdy∫02∫0r2−y2∫0r2−x2−y2dzdxdy