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Onto Function or Surjective - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

  • Onto Function or Surjective is considered one the most difficult concept.

  • 13 Questions around this concept.

Solve by difficulty

f:(,)[0,),f(x)=x2 is a/an:

Find the number of onto functions from A to B where n(A)=5 and n(B)=3.

Concepts Covered - 1

Onto Function or Surjective

A function f:XY is said to be onto (or surjective), if every element of Y is the image of some element of X under f, i.e., for every yY, there exists an element x in X such that f(x)=y

Hence, Range = co-domain for an onto function

Some examples of onto function
Consider, X={x1,x2,x3,x4} and Y={y1,y2,y3}

f:XY
 

As every element in Y has a pre-image in X, so it is an onto function

Method to show onto or surjective

Find the range of y=f(x) and show that range of f(x)= co-domain of f(x)

 

Number of onto functions = \sum_{r=1}^{n}\left ( -1 \right )^{n-r}n_{C_{r}}r^{m}

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Onto Function or Surjective

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