Q.If \(a+\cfrac{1}{a}=\sqrt{3}\), then the value of \(a^3+\cfrac{1}{a^3}\) will be — (a) 1 (b) 0 (c) -1 (d) 3
Answer: B
\(a^3+\cfrac{1}{a^3}\) \(=(a+\cfrac{1}{a})^3 - 3 \cdot a \cdot \cfrac{1}{a} \cdot (a+\cfrac{1}{a})\) \(=(\sqrt{3})^3 - 3\sqrt{3}\) \(= 3\sqrt{3} - 3\sqrt{3}\) \(= 0\)
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