DSSSB TGT CS Mock 02 – Question 054

Question:

If \(x + \frac{1}{x} = 4\), find the value of \(x^3 + \frac{1}{x^3}\).

यदि \(x + \frac{1}{x} = 4\) है, तो \(x^3 + \frac{1}{x^3}\) का मान ज्ञात कीजिए।

Options:

  • 52
  • 64
  • 48
  • 56
  • 52
  • 64
  • 48
  • 56

Correct Answer: a)

Explanation:

Using the identity: \(x^3 + \frac{1}{x^3} = \left(x + \frac{1}{x}\right)^3 – 3\left(x + \frac{1}{x}\right)\)
\(= 4^3 – 3(4) = 64 – 12 = \textbf{52}\) (Option a).

सर्वसमिका: \(x^3 + \frac{1}{x^3} = (x + \frac{1}{x})^3 – 3(x + \frac{1}{x}) = 4^3 – 3(4) = 64 – 12 = \textbf{52}\) (विकल्प a)।

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