г) \(\frac{2mn}{m^2-n^2} + \frac{m^2+n^2}{m^2-n^2} = \frac{2mn+m^2+n^2}{m^2-n^2} = \frac{m^2+2mn+n^2}{m^2-n^2} = \frac{(m+n)^2}{(m-n)(m+n)} = \frac{m+n}{m-n}\)
Ответ: \(\frac{m+n}{m-n}\)