Q43 / 90 · JEE Main 2023 (13 Apr Shift 1) · Mathematics

For the differentiable function f:ℝ-{0}-ℝ, let 3fx+2f1x=1x-10, then f3+f'14 is equal to

  • A
    335
  • B
    8
  • C
    295
  • Correct answer
    D
    13

Solution

Given:

3fx+2f1x=1x-10   ....1

Replace x→1x

3f1x+2fx=x-10   ....2

Eliminating f1x from 1 & 2, we get

⇒5fx=3x-2x-10

Let us replace x with 3

⇒5f3=33-23-10

⇒f3=-3

⇒5f'x=-3x2-2

⇒5f'14=-48-2

⇒f'14=-10

⇒f(3)+f'14=13

Hence this is the correct option.

Hence, the correct answer is option: 'D'.

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