Question

Calculati $x^{2} + \frac{1}{ x^{2} } stiind ca x + \frac{1}{x} =3$

Answer 1

x+$\frac{1}{x}$=3 ridicam toata ecuatia la puterea a2a si avem asa:
(x+$\frac{1}{x}$)²=9
x²+$\frac{1}{ x^{2} }$+1=9
=> x² + $\frac{1}{ x^{2} }$=8