Practicing Success
If $(x + \frac{1}{x})=\frac{11}{5}$, what is the value of $(x^3 + \frac{1}{x^3})$ ? |
$4\frac{6}{125}$ $5\frac{101}{125}$ $10\frac{81}{125}$ $17\frac{31}{125}$ |
$4\frac{6}{125}$ |
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 × $\frac{11}{5}$ = $\frac{1331}{125}$ - $\frac{33}{5}$ = $\frac{1331 - 825}{125}$ = $\frac{506}{125}$ = $4\frac{6}{125}$ |