Question : If $\small x-\frac{1}{x}=2$, then the value of $x^{3}-\frac{1}{x^{3}}$ is:
Option 1: 15
Option 2: 2
Option 3: 14
Option 4: 11
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Correct Answer: 14
Solution : Given: $\small x-\frac{1}{x}=2$ We know that $(a-b)^3=a^3-b^3-3ab(a-b)$ So, $(x-\frac{1}{x})^3=x^3-\frac{1}{x^3}-3(x-\frac{1}{x})$ Substituting the given values, we get ⇒ $2^3=x^3 - \frac{1}{x^3}-3(2)$ ⇒ $x^3 - \frac{1}{x^3}=14$ Hence, the correct answer is 14.
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Question : If $x^2+\frac{1}{x^2}=4$, then what is the value of $x^4+\frac{1}{x^4}$?
Option 1: 16
Option 2: 14
Option 3: 12
Option 4: 20
Question : If $x>1$ and $x+\frac{1}{x}=2\frac{1}{12}$, then the value of $x^{4}-\frac{1}{x^{4}}$ is:
Option 1: $\frac{58975}{20736}$
Option 2: $\frac{59825}{20736}$
Option 3: $\frac{57985}{20736}$
Option 4: $\frac{57895}{20736}$
Question : If $x+\frac{1}{x}=3$, then the value of $\frac{3x^{2}-4x+3}{x^{2}-x+1}$ is:
Option 1: $\frac{4}{3}$
Option 2: $\frac{3}{2}$
Option 3: $\frac{5}{2}$
Option 4: $\frac{5}{3}$
Question : If $x+\frac{1}{x}=2$, then the value of $x^{11}+\frac{1}{x^{20}}$ is:
Option 1: 0
Option 2: 1
Option 3: 2
Option 4: 7
Question : If $2 x+\frac{2}{x}=5$, then the value of $\left(x^3+\frac{1}{x^3}+2\right)$ will be:
Option 1: $\frac{81}{11}$
Option 2: $\frac{81}{7}$
Option 3: $\frac{71}{8}$
Option 4: $\frac{81}{8}$
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