# Fractions in Einstein Relativity Theory

Norway

## Homework Statement

From the formula $$t = \frac{L}{v+c} + \frac{L}{v-c}$$ I've made $$t = \frac{2L}{c}\left(\frac{1}{1 - \frac{v^2}{c^2}}\right)$$. This is the problem:
$$\left(\frac{1}{1 - \frac{v^2}{c^2}}\right) = \left(\frac{1 + \frac{v^2}{c^2}}{1 - \left(\frac{v^2}{c^2}\right)^2}\right)$$
How?

## Homework Equations

That's kinda what I'm asking for. :-b

## The Attempt at a Solution

I've gotten this far, but no more. I've tried to see how they relate, but I can't figure anything out.

Staff Emeritus
$$\left(\frac{1 + \frac{v^2}{c^2}}{1 - \left(\frac{v^2}{c^2}\right)^2}\right)$$
You remember what $$x^2 - y^2$$ equals to?