Question

Como resolver:

x+1/x-1 + x-1/x+1

Answer 1

$\frac{x+1}{x-1}+\frac{x-1}{x+1}=\frac{(x+1)^2+(x-1)^2}{x^2-1}=\frac{x^2+2x+1+x^2-2x+1}{x^2-1}=\frac{2(x^2+1)}{x^2-1}$

Answer 2

$\frac{x+1}{x-1} + \frac{x-1}{x+1}\\ \\ \frac{(x+1)^2+(x-1)^2}{x^2+1} \\ \frac{x^2+2x+1+x^2-2x+1}{x^2-1}\\ \\ \frac{2x^2+2}{x^2-1}= \frac{2(x^2+1)}{x^2-1}$