ISRO Electrical Engineering (EE) 2013 - Question 74

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The minimum point of the function (x^3/3) – x is at

  • A. x = 1
  • B. x = –1
  • C. x = 0
  • D. x = 1/√3

Answer: A. x = 1

Explanation: f'(x) = x² − 1 = 0 gives critical points x = ±1. Since f''(x) = 2x, f''(1) = 2 > 0 indicates a local minimum at x = 1.

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