If mx^m-nx^n = 0 then what is the value of 1/(x^m+x^n)+1/(x^m-x^n) in…

$\frac{2mn}{x^n(n^2+m^2)}$

$\frac{2m}{x^n(m^2-n^2)}$

$\frac{2mn}{x^n(n^2-m^2)}$

$\frac{2mn}{x^n(m^2-n^2)}$