Question

Simplify:

(a^-1 - b^-1) / (a^-1 + b^-1)

Answer 1

$\frac{ {a}^{ - 1} - {b}^{ - 1} }{ {a}^{ - 1} + {b}^{ - 1} } \\ \\ = \frac{ \frac{1}{a} - \frac{1}{b} }{ \frac{1}{a} + \frac{1}{b} } \\ \\ = \frac{b - a}{b + a}$