If $x + \frac{1}{x} = -2\sqrt{3}$, what is the value of $x^5 +\frac{1}{x^5}$ ? |
$-178\sqrt{3}$ $-182\sqrt{3}$ $182\sqrt{3}$ $-180\sqrt{3}$ |
$-178\sqrt{3}$ |
We know that, x5 + $\frac{1}{x^5}$ = (x2 + $\frac{1}{x^2}$) × (x3 + $\frac{1}{x^3}$) – (x + $\frac{1}{x}$) We also know that, If $K+\frac{1}{K}=n$ then, $K^2+\frac{1}{K^2}$ = n2 – 2 If x + \(\frac{1}{x}\) = n then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n So, If $x + \frac{1}{x} = -2\sqrt{3}$, Then the value of (x2 + $\frac{1}{x^2}$) = ($-2\sqrt{3}$)2 – 2 = 10 and, $x^3 +\frac{1}{x^3}$ = ($-2\sqrt{3}$)3 - 3 × $-2\sqrt{3}$ = $-24\sqrt{3}$ + $6\sqrt{3}$ = $-18\sqrt{3}$ what is the value of $x^5 +\frac{1}{x^5}$ = ($-18\sqrt{3}$) (10) - ($-2\sqrt{3}$)= $-178\sqrt{3}$ |