If $\frac{K}{k^2-2k+1}=\frac{1}{6}$, then what is the value of $\frac{1}{k^3}+k^3$ ?
Answer & explanation
Correct answer: option 2
If x + \(\frac{1}{x}\) = n
then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n
If $\frac{K}{k^2-2k+1}=\frac{1}{6}$
Then, $\frac{1}{k^3}+k^3$ = ?
$k^2$-2k+1 = 6k
= $k^2$-8k+1 = 0
Divide the equation by k on both sides,
k + \(\frac{1}{k}\) = 8
$x^3 +\frac{1}{x^3}$ = 83 - 3 × 8
$x^3 +\frac{1}{x^3}$ = 512 - 24 = 492