Question

E(x) = (1/X la a doua + 1/X ) ori X la a treia/X + 1 .
Aratati ca E(x)=x

Answer 1

$(\frac{1}{x^{2} } + \frac{1}{x} )* \frac {x^{3}}{x+1} = (\frac{1}{x^{2} } + \frac{x}{x^2} )* \frac {x^{3}}{x+1}=\frac{x+1}{x^{2} } *\frac {x^{3}}{x+1}= \frac{x^3}{x^2}=x$