Download the app

Questions  

 If the functions f(x) and g(x) are defined on RR such  that f(x)=0,x rational x,x irrational 

 and g(x)=0,x irrational x,x rational  then (fg)(x) is 

a
one-one and onto
b
neither one-one nor onto
c
one-one but not onto
d
onto but not one-one

detailed solution

Correct option is A

We are given thatf:R→R,f(x)=0,x∈ rational x,x∈ irrational g:R→R,g(x)=0,x∈ irrational x,x∈ rational ∴ (f−g):R→R such that (f−g)(x)=−x, if x∈ rational x, if x∈ irrational  Since (f−g):R→R for any x, there is only one value of  ( f(x)−g(x)) whether x is rational or irrational. Moreover,  as x∈R,f(x)−g(x) also belongs to R . Therefore, (f−g) is one-one and onto.

Talk to our academic expert!

+91

Are you a Sri Chaitanya student?


Similar Questions

Which of the following statements are incorrect?

 I. If f(x) and g(x) are one-one then f(x)+g(x) is also one-one

 II. If f(x) and g(x) are one-one then f(x)g(x) is also one-one

 III. If f(x) is odd then it is necessarily one-one. 


phone icon
whats app icon