Question

Stiind ca x- 1/x=2 ,calculați x la patrat + 1/x la patrat

Answer 1

$x- \frac{1}{x}=2 \\ (x- \frac{1}{x})^2=2^2 \\ x^{2} -2*x* \frac{1}{x}+ \frac{1}{ x^{2} } =4 \\ x^{2} + \frac{1}{ x^{2} } =4+2 \\ x^2+ \frac{1}{x^2}=6$