Question

VĂ ROG! AJUTATI-MA! Calculati:
1/x²+1/y²+2/xy-1/x²y², x+y=1, unde x, y∈R*.
/= fractie

Answer 1

$( \frac{1}{x}+ \frac{1}{y})^2- \frac{1}{xy}=( \frac{x+y}{xy})^2- \frac{1}{xy}= \frac{1}{xy}- \frac{1}{xy}=0$