Question

Срочно пж!!!¡!!!!¡¡!!!!!!!!

Answer 1

Объяснение:

$\displaystyle\\1)\ \frac{1}{a-b} +\frac{1}{a+b}=\frac{a+b+a-b}{(a-b)*(a+b)} =\frac{2a}{a^2-b^2} .\\\\\\2)\ \frac{2a}{a^2-b^2}+\frac{2a}{a^2+b^2} =\frac{2a*(a^2+b^2)+2a*(a^2-b^2)}{(a^2-b^2)*(a^2+b^2)}=\frac{2a^3+2ab^2+2a^3-2ab^2}{a^4-b^4} =\\\\\\=\frac{4a^3}{a^4-b^4} .\\\\\\3)\ \frac{4a^3}{a^4-b^4}+\frac{4a^3}{a^4+b^4}= \frac{4a^3*(a^4+b^2)+4a^3*(a^4-b^4)}{(a^4-b^4)*(a^4+b^4)}=\\\\\\=\frac{4a^7+4a^3b^4+4a^7-4a^3b^4}{a^8-b^8}=\frac{8a^7}{a^8-b^8}.$