Careers360 Logo
ask-icon
share
    How to Prepare for AP EAMCET with JEE Main 2026 - Detailed Study Plan

    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.

    • 14 Questions around this concept.

    Solve by difficulty

    $f:(-\infty, \infty) \rightarrow[0, \infty), f(x)=x^2$ 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 $f: X \rightarrow Y$ 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 $y \in Y$, 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, $X=\left\{x_1, x_2, x_3, x_4\right\}$ and $Y=\left\{y_1, y_2, y_3\right\} \mid$

    $
    f: X \rightarrow Y
    $
     

    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}

    Study it with Videos

    Onto Function or Surjective

    "Stay in the loop. Receive exam news, study resources, and expert advice!"

    Get Answer to all your questions