Question

ДАЮ 25 БАЛЛОВ!срочно!!!
!!!

Answer 1

Ответ:

$\displaystyle x=0,2^{-1}=\Big(\frac{2}{10}\Big)^{-1}=\Big(\frac{1}{5}\Big)^{-1}=5\\\\\\\frac{2x^{-2}}{1-x^{-2}}-\frac{2x^{-2}}{1+x^{-2}}=\frac{2\cdot \dfrac{1}{x^2}}{1-\dfrac{1}{x^2}}-\frac{2\cdot \dfrac{1}{x^2}}{1+\dfrac{1}{x^2}}=\frac{2}{x^2\cdot \dfrac{x^2-1}{x^2}}-\frac{2}{x^2\cdot \dfrac{x^2+1}{x^2}}=\\\\\\=\frac{2}{x^2-1}-\frac{2}{x^2+1}=\frac{2(x^2+1)-2(x^2-1)}{(x^2-1)(x^2+1)}=\frac{4}{x^4-1}=\\\\\\=\frac{2}{5^4-1}=\frac{4}{625-1}=\dfrac{4}{624}=\frac{1}{156}$