badge image

Enroll For Free Now & Improve Your Performance.

User Icon
User Icon
User Icon
User Icon
User Icon

Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.

Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: 12


if the function satisfies the relation f(x+y)=y|x-1|/(x-1)f(x)+f(y) with f(1)=2, then lim f`(x) where x tends to 1 is

6 years ago

Answers : (1)

Nirmal Singh.
askIITians Faculty
44 Points
							f(x+y)=[y|x-1| ]/ [(x-1)f(x)+f(y)]
We take log on both sides and have
Log f(x+y) = log y + log mod x-1 –log (x-1) f(x) +f(y0
We find derivatie now
F’(x+y)(1+y’)/f(x+y) = y’/y + 1/mod x-1 -1/x-1 f(x) + f(y)
When x>1 1/x-1 absolute value = 1/x-1.
When x<1 we cannot find as x-1 becomes negative and log does not exist for negative numbers.
As here y is also there, I am unable to arrive at the exact answer for f’(x)
If it single variable easily we can find out
So what we do is we put x=1 and y =0 and try that
We get f(1) =2 which means 2
Nirmal Singh
Askiitians Faculty
6 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 731 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 51 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details