Q50 / 90 · JEE Main 2024 (30 Jan Shift 2) · Mathematics

Let f:R-{0}→R be a function satisfying fxy=f(x)f(y) for all x,y,f(y)≠0. If f'(1)=2024, then

  • Correct answer
    A
    xf'x-2024fx=0
  • B
    xf'x+2024fx=0
  • C
    x'(x)+f(x)=2024
  • D
    xf'(x)-2023f(x)=0

Solution

Given: fxy=fxfy

And we know that, if fxy=fxfy then fx=xn.

So, differentiating the function we get,

f'x=nxn-1 and given f'1=2024.

Hence, on comparing we get, n=2024

⇒xf'x=x×2024x2023

⇒xf'x=2024x2024

⇒xf'x-2024x2024=0

⇒xf'x-2024fx=0

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

Relevant Questions