Many One Function - Practice Questions & MCQ

A function $f: X \rightarrow Y$ is called a many one function, if two or more elements of set $X$ have the same image in set $Y$,

Or we can say that if $f: X \rightarrow Y$ is many- one if it is not one-one function.
To check it graphically a line parallel to $x$-axis cuts the curve at more than one point.

Both are many one, as in both there are two elements $x_2, x_3$ which corresponds to the same image $y_3$, i.e. $f\left(x_2\right)=f\left(x_3\right)=y_3$

Method to check many-one

Check whether the function is one-one or not. If the function is not one-one then it is a many-one function.