Limits Continuity And Differentiability Question 23

Question: If $ y=\frac{1}{t^{2}+t-2} $ where $ t=\frac{1}{x-1} $ , then find the number of points of discontinuities of $ y=f(x), $ ,

Options:

A) 1

B) 2

C) 3

D) 4

Show Answer

Answer:

Correct Answer: C

Solution:

$ t=\frac{1}{x-1} $ is discontinuous at $ x=1. $ Also $ y=\frac{1}{t^{2}+t-2} $ discontinuous at $ t=-2 $ and $ t=1 $

When $ t=-2,\frac{1}{x-1}=-2\Rightarrow x=\frac{1}{2} $

When $ t=1,\frac{1}{x-1}\Rightarrow x=2 $ So, $ y=f(x) $ is discontinuous at three points $ x=1,\frac{1}{2},2 $