Question

сколько будет срочно!!!!!​

Answer 1

$\frac{b}{1-b^{2} } +\frac{1}{1+b} = \frac{b*(1+b)}{(1+b)*(1-b^{2}) } +\frac{1-b^{2}}{(1+b)*(1-b^{2})} = \frac{b*(1+b)+(1-b^{2})}{(1+b)*(1-b^{2}) } = \frac{b+b^{2}+1-b^{2}}{(1+b)*(1-b^{2}) } = \frac{b+1}{(1+b)*(1-b^{2}) } = \frac{1}{1-b^{2} }$