Chapter 9, Problem 22MS

To determine

To Simplify: The expression and assume that no denominator is zero.

Answer to Problem 22MS

  $\frac{2st}{(s-t)(s+t)}$

Explanation of Solution

Given: $\frac{s}{s-t}-\frac{s}{s+t}$

Given: $\frac{s}{s-t}-\frac{s}{s+t}$

Solving by taking LCM

  $\begin{array}{l}=\frac{s}{s-t}-\frac{s}{s+t}\\ =\frac{s(s+t)-s(s-t)}{(s-t)(s+t)}\\ =\frac{s^2+st-s^2+st}{(s-t)(s+t)}\\ =\frac{2st}{(s-t)(s+t)}\end{array}$

Hence, $\frac{2st}{(s-t)(s+t)}$