Răspuns :
[tex]S=x+\frac{1}{x}=4\\
P=x\cdot\frac{1}{x}=1\\
x^2+\frac{1}{x^2}=S^2-2P=16-2=14\\
x^3+\frac{1}{x^3}=(x+\frac{1}{x})(x^2-x\frac{1}{x}+\frac{1}{x^2})=S(S^2-3P)=4\cdot13=52\\
x^4+\frac{1}{x^4}=(x^2+\frac{1}{x^2})^2-2x^2\frac{1}{x^2}=14^2-2=196-2=194[/tex]