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The function f(x) = cot−1 x + x increases in the interval

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Question

The function f(x) = cot−1 x + x increases in the interval

Options

  • (1, ∞)

  • (−1, ∞)

  • (−∞, ∞)

  • (0, ∞)

MCQ
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Solution

(−∞, ∞)

\[f\left( x \right) = \cot^{- 1} x + x\]

\[f'\left( x \right) = \frac{- 1}{1 + x^2} + 1\]

\[ = \frac{- 1 + 1 + x^2}{1 + x^2}\]

\[ = \frac{x^2}{1 + x^2} \geq 0, \forall x \in R\]

\[\text { So,f(x)is increasing on } \left( - \infty , \infty \right) .\]

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Chapter 16: Increasing and Decreasing Functions - Exercise 17.4 [Page 40]

APPEARS IN

R.D. Sharma Mathematics Volume 1 and 2 [English] Class 12
Chapter 16 Increasing and Decreasing Functions
Exercise 17.4 | Q 2 | Page 40

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