Question

Se
a= 1 sob x+1 , e , b= 1 sob x-1 . Calcule a +b

Answer 1

Oi Segue: 

a+b

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

:)