Q. If $f(x) = \left\{ \begin{array}{r} x\sin\frac{1}{x},\ \ x \neq 0 \\ k,\ \ \ \ \ \ \ \ \ \ \ x = 0 \end{array} \right.\$ is continuous at $x = 0$, then the value of $k$ is

A) 1
B) -1
C) 0
D) 2
Explanation

(c)
If function $f(x)$ is continuous at $x = 0$, then
$f(0) = \lim_{x \rightarrow 0}{f(x)}$
$\therefore\ \ \ f(0) = k = \lim_{x \rightarrow 0}{x\sin\frac{1}{x}}$
$\Rightarrow k = 0$ $\left\lbrack \because - 1 \leq \sin\frac{1}{x} \leq 1 \right\rbrack$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.