Functions Question 8

Question: If $ f(x)= \begin{cases} & x\sin x,,\text{when }0<x\le \frac{\pi }{2} \\ & \frac{\pi }{2}\sin (\pi +x),when\frac{\pi }{2}<x<\pi \\ \end{cases} . $ , then

[IIT 1991]

Options:

A) $ f(x) $ is discontinuous at $ x=\pi /2 $

B) $ f(x) $ is continuous at $ x=\pi /2 $

C) $ f(x) $ is continuous at $ x=0 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

$ \underset{x\to \infty }{\mathop{\lim }}\frac{4x}{(\sqrt{x^{2}+8x+3}+\sqrt{x^{2}+4x+3}} $ and $ f( \frac{\pi }{2} )=\frac{\pi }{2}. $