Question

Consider the four functions $f_1, f_2, f_3$ and $f_4$ as follows


Choose the correct option.

• A. $f_1$ and $f_2$ are onto
• B. $f_2$ and $f_4$ are onto
• C. $f_2$ and $f_3$ are onto
• D. $f_3$ and $f_4$ are onto

Answer 1

Answer: (D)

The function $f_3$ and $f_4$ in (iii), (iv) are onto and the function $f_1$ in (i) is not onto as elementse, $f$ in $X_2$ are not the image of any element in $X_1$ under $f_1$. Similarly, $f_2$ is not onto.