# Math Help - Rationalizing the Denominator

1. ## Rationalizing the Denominator

x^2 / (Square Root(x+1)) - (Square Root(x-1))

How to I multiply the conjugate on the bottom? I really just don't know how to do it

2. ## Re :

$
\frac{x^2}{\sqrt{x+1}-\sqrt{x-1}}$

Multiply the top and bottom by $\frac{\sqrt{x+1}+\sqrt{x-1}}{\sqrt{x+1}+\sqrt{x-1}}$

and hence it equals $\frac{x^2}{2}(\sqrt{x+1}+\sqrt{x-1})$

Use $(a+b)(a-b)=a^2-b^2$