Practicing Success
Practicing Success
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If $x^2-\sqrt{11} x+1=0$, then $\left(x^3+x^{-3}\right)=$ |
$8 \sqrt{11}$ $10 \sqrt{11}$ $4 \sqrt{11}$ $7 \sqrt{11}$ |
$8 \sqrt{11}$ |
If $x^2-\sqrt{11} x+1=0$ divide by x on both sides, x + \(\frac{1}{x}\) = \(\sqrt {11}\) If x + \(\frac{1}{x}\) = n then, $x^3 +\frac{1}{x^3}$ = n3 - 3 × n $x^3 +\frac{1}{x^3}$ = (\(\sqrt {11}\))3 - 3 × \(\sqrt {11}\) = $8 \sqrt{11}$ |
