If \(x = \sqrt{3} + \sqrt{2}\), what is the value of \(x^3 + \frac{1}{x^3}\)?
A. \(30\sqrt{3}\)
B. \(18\sqrt{3}\)
C. \(24\sqrt{3}\)
D. \(12\sqrt{3}\)
A. \(30\sqrt{3}\)
B. \(18\sqrt{3}\)
C. \(24\sqrt{3}\)
D. \(12\sqrt{3}\)
Best answer
Answer: B. \(18\sqrt{3}\)
Answer: (B) \(18\sqrt{3}\)
\(\frac{1}{x} = \sqrt{3} - \sqrt{2}\), so \(x + \frac{1}{x} = 2\sqrt{3}\).
\(x^3 + \frac{1}{x^3} = (2\sqrt{3})^3 - 3(2\sqrt{3}) = 24\sqrt{3} - 6\sqrt{3} = 18\sqrt{3}\).
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