If $(x + \frac{1}{x})=\frac{11}{5}$, what is the value of $(x^3 + \frac{1}{x^3})$ ?
Answer & explanation
Correct answer: option 1
We know that,
If x + \(\frac{1}{x}\) = n
then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n
If $x + \frac{1}{x}=\frac{11}{5}$,
then, the value of $x^3 + \frac{1}{x^3}$ = ($\frac{11}{5}$)3 - 3 × $\frac{11}{5}$
= $\frac{1331}{125}$ - $\frac{33}{5}$
= $\frac{1331 - 825}{125}$
= $\frac{506}{125}$ = $4\frac{6}{125}$