Target Exam

CUET

Subject

Maths. Section B1

Chapter

Continuity and Differentiability

Question:

Discuss the continuity of the function $f$ defined by $f(x) = \frac{1}{x}, x \neq 0$.

Options:

Continuous for all $x \in \mathbb{R}$.

Continuous at every point in its domain $(x \neq 0)$.

Discontinuous everywhere.

Continuous only for positive values of $x$.

Correct Answer:

Continuous at every point in its domain $(x \neq 0)$.

Explanation:

The correct answer is Option (2) → Continuous at every point in its domain $(x \neq 0)$. ##

Fix any non zero real number $c$, we have

$\lim\limits_{x \to c} f(x) = \lim\limits_{x \to c} \frac{1}{x} = \frac{1}{c}$

Also, since for $c \neq 0$, $f(c) = \frac{1}{c}$, we have $\lim\limits_{x \to c} f(x) = f(c)$ and hence, $f$ is continuous at every point in the domain of $f$. Thus $f$ is a continuous function.