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If the largest interval of x in which the function f x = x 3 - 3 x + 1 is decreasing is a , b , then the value of a + 2 b is equal to

Options

  1. A– 1
  2. B0
  3. C1
  4. D2

Correct answer

C. 1

Step-by-step solution

As f ' x = 3 x 2 - 3 = 3 x - 1 x + 1 i.e. the largest interval in which f x decreases is - 1,1 ⇒ a = - 1 b = 1 ∴ a + 2 b = 1

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