## Calculus (3rd Edition)

(a) $\frac{d}{dR}R=1$. (b) $\frac{d}{dR}r=0$. (c) $\frac{d}{dR}r^2R^3=3r^2R^2$.
(a) $\frac{d}{dR}R=1$. (b) Since $r$ is constant, we have $\frac{d}{dR}r=0$. (c) Since $r$ is constant, we have $\frac{d}{dR}r^2R^3=3r^2R^2$.