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1.Stiind ca a+ [tex] \frac{1}{a} [/tex] = [tex] \frac{5}{2} [/tex] , unde a este numar real nenul , aratati ca a² + [tex] \frac{1}{ a^{2} } [/tex] = [tex] \frac{17}{ 4 } [/tex]
2.Stiind ca x+ [tex] \frac{1}{x}[/tex] =-2 , unde x este numar real nenul ,aratati ca x²+ [tex] \frac{1}{ x^{2} } [/tex]=2


Răspuns :

1.
a+1/a=5/2  ridicam la puterea 2
(a+1/a)²=(5/2)²
a²+2×a×1/a+1/a²=25/4
a²+2+1/a²=25/4
a²+1/a²=25/4-2
a²+1/a²=(25-2×4)/4
a²+1/a²=(25-8)/4
a²+1/a²=17/4


2.
x+1/x=-2  ridicam la puterea 2
(x+1/x)²=(-2)²
x²+2x×1/x+1/x²=4
x²+2+1/x²=4
x²+1/x²=4-2
x²+1/x²=2