Question

solve the given formula for the indicated variable. electricity $\frac{1}{r}=\frac{1}{r_1}+\frac{1}{r_2}$ for r

Explanation:

Step1: Find a common - denominator for the right - hand side

The common denominator of $\frac{1}{R_1}$ and $\frac{1}{R_2}$ is $R_1R_2$. So $\frac{1}{R}=\frac{R_2 + R_1}{R_1R_2}$.

Step2: Cross - multiply

Cross - multiplying gives $R_1R_2=R(R_1 + R_2)$.

Step3: Solve for R

Divide both sides of the equation $R_1R_2=R(R_1 + R_2)$ by $(R_1 + R_2)$ to get $R=\frac{R_1R_2}{R_1 + R_2}$.

Answer:

$\frac{R_1R_2}{R_1 + R_2}$