Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

Match List-I with List-II

Let $f: A → B$ be a function given by $f(x) = x^2$

List-I Domain and Co-domain

List-II Kind

(A) $A= R$ and $B = R$

(I) $f$ is both one-one and onto

(B) $A= R$ and $B = [0, ∞]$

(II) $f$ is one-one but not onto

(C) $A= B = [0, ∞]$

(III) $f$ is not one-one but onto

(D) $A= [0, ∞]$ and $B = R$

(IV) $f$ is neither one-one nor onto

Choose the correct answer from the options given below:

Options:

(A)-(III), (B)-(IV), (C)-(II), (D)-(I)

(A)-(IV), (B)-(III), (C)-(I), (D)-(II)

(A)-(IV), (B)-(III), (C)-(II), (D)-(I)

(A)-(III), (B)-(IV), (C)-(I), (D)-(II)

Correct Answer:

(A)-(IV), (B)-(III), (C)-(I), (D)-(II)

Explanation:

The correct answer is Option (2) → (A)-(IV), (B)-(III), (C)-(I), (D)-(II)

List-I Domain and Co-domain

List-II Kind

(A) $A= R$ and $B = R$

(IV) $f$ is neither one-one nor onto

(B) $A= R$ and $B = [0, ∞]$

(III) $f$ is not one-one but onto

(C) $A= B = [0, ∞]$

(I) $f$ is both one-one and onto

(D) $A= [0, ∞]$ and $B = R$

(II) $f$ is one-one but not onto

Given $f(x)=x^{2}$.

(A) $A=\mathbb{R},\;B=\mathbb{R}$: $f$ is not one-one since $f(1)=f(-1)$ and not onto since negative values are not in the range.

So (A) → (IV).

(B) $A=\mathbb{R},\;B=[0,\infty)$: not one-one but onto because every non-negative real has a square root.

So (B) → (III).

(C) $A=B=[0,\infty)$: one-one and onto since $x^{2}$ is strictly increasing on $[0,\infty)$ and covers all $[0,\infty)$.

So (C) → (I).

(D) $A=[0,\infty),\;B=\mathbb{R}$: one-one but not onto since negative values are not attained.

So (D) → (II).

Final answer: (A)–(IV), (B)–(III), (C)–(I), (D)–(II)