Ex 1.3, 14 - Let f (x) = 4x/3x+4. Inverse of f is - Class 12

Ex 1.3 , 14 - Chapter 1 Class 12 Relation and Functions - Part 2

Take a fresh quiz. Then take another.
Every attempt is a new AI-adaptive Teachoo quiz with 3 questions, selected from your answers, mistakes, and progress.
Remove Ads
Teachoo ยท Class 12 Explore Class 12

Transcript

Ex 1.3, 14 Let f : R โ€“ {(โˆ’4)/3} โ†’ R be a function defined as f (x) = 4๐‘ฅ/(3๐‘ฅ + 4) The inverse of f is map g: Range f โ†’ R โ€“ {(โˆ’4)/3}given by (A) g (y) = 3๐‘ฆ/(3โˆ’4๐‘ฆ) (B) g (y) = 4๐‘ฆ/(4โˆ’3๐‘ฆ) (C) g (y) = 4๐‘ฆ/(3โˆ’4๐‘ฆ) (D) g (y) = 3๐‘ฆ/(4โˆ’3๐‘ฆ) f(x) = 4๐‘ฅ/(3๐‘ฅ + 4) Calculating inverse Take f(x) = y Hence, equation becomes y = 4๐‘ฅ/(3๐‘ฅ + 4) y(3x + 4) = 4x 3xy + 4y = 4x 3xy โ€“ 4x = โ€“ 4y x(3y โ€“ 4) = โ€“ 4y x = (โˆ’4๐‘ฆ)/(3๐‘ฆ โˆ’ 4) x = (โˆ’4๐‘ฆ)/(โˆ’1(โˆ’3๐‘ฆ + 4)) x = 4๐‘ฆ/((4 โˆ’ 3๐‘ฆ)) So, inverse of f = 4๐‘ฆ/((4 โˆ’ 3๐‘ฆ)) โˆด g(y) = 4๐‘ฆ/((4 โˆ’ 3๐‘ฆ)) Hence, B is the correct answer

Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh is an IIT Kanpur graduate and has been teaching for 16+ years. At Teachoo, he breaks down Maths, Science and Computer Science into simple steps so students understand concepts deeply and score with confidence.

Many students prefer Teachoo Black for a smooth, ad-free learning experience.