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If f(x)=x-42x, then f'(1) is ______. - Mathematics

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Question

if `f(x) = (x - 4)/(2sqrt(x))`, then f'(1) is ______.

Options

  • `5/4`

  • `4/5`

  • 1

  • 0

MCQ
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Solution

if `f(x) = (x - 4)/(2sqrt(x))`, then f'(1) is `5/4`.

Explanation:

Given that `f(x) = (x - 4)/(2sqrt(x))`

∴ f'(x) = `1/2[(sqrt(x) * 1 - (x - 4) * 1/(2sqrt(x)))/x]`

= `1/2 [(2x - x + 4)/(2sqrt(x) * 4)]`

= `1/2[(x + 4)/(2(x)^(3/2))]`

∴ f'(x) at x = 1

= `1/2 [(1 + 4)/(2 xx 1)]`

= `5/4`

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Chapter 13: Limits and Derivatives - Exercise [Page 244]

APPEARS IN

NCERT Exemplar Mathematics [English] Class 11
Chapter 13 Limits and Derivatives
Exercise | Q 69 | Page 244

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