If $x + \frac{1}{x} = 5, x ≠ 0 $ then the value of $\frac{x^4+\frac{1}{x^2}}{x^2-3x+1}$ is equal to :
Answer & explanation
Correct answer: option 1
$x + \frac{1}{x} = 5, x ≠ 0 $
then the value of $\frac{x^4+\frac{1}{x^2}}{x^2-3x+1}$
We know that,
If x + \(\frac{1}{x}\) = n
then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n
Divide numerator and denominator by x we get,
We can write $\frac{x^3+\frac{1}{x^3}}{x-3+\frac{1}{x}}$
= $x^3 +\frac{1}{x^3}$ = 53 - 3 × 5 = 110
Put this value in $\frac{x^3+\frac{1}{x^3}}{x-3+\frac{1}{x}}$
= $\frac{110}{5-3}$ = 55