10 . (a) \underset{R_{1}}{\longrightarrow} \underset{R_{2}}{\mathcal{M} M} Prove that R=R_{1}+R_{2} Where R is the equivalent. resistance of resistors R_{1} and R_{2} connected in series. (b) Prove that \frac{1}{R}=\frac{1}{R_{1}}+\frac{1}{R_{2}} Where R is the equivalent. resistance of resistors R_{1} and R_{2} connected in parallel.