Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

Let $f: R→R$ be defined as $f(x) = 10x$. Then (Where R is the set of real numbers)

Options:

f is both one-one and onto

f is onto but not one-one

f is one-one but not onto

f is neither one-one nor onto

Correct Answer:

f is both one-one and onto

Explanation:

The correct answer is Option (1) → f is both one-one and onto

$f:\mathbb{R}\to \mathbb{R}$ is defined by $f(x)=10x$.

Domain of $f$ is $\mathbb{R}$ because every real $x$ is allowed.

Range of $f$ is also $\mathbb{R}$ because $10x$ covers all real values as $x$ varies over $\mathbb{R}$.

Thus $f$ is both one–one and onto.

Final answer: the domain is $\mathbb{R}$ and the range is $\mathbb{R}$