This is LaTeX code:
[latex]
\frac{1}{4} \cdot ( \sqrt{x+\sqrt{x^2-1}}-\sqrt{x-\sqrt{x^2-1}})= \frac{1}{4} \cdot \frac{( \sqrt{x+\sqrt{x^2-1}}-\sqrt{x-\sqrt{x^2-1}})( \sqrt{x+\sqrt{x^2-1}}+\sqrt{x-\sqrt{x^2-1}})}{ \sqrt{x+\sqrt{x^2-1}}+\sqrt{x-\sqrt{x^2-1}}}=
[/latex]