Functions Question 680

Question: $ \underset{x\to 1}{\mathop{\lim }},\frac{1}{|1-x|}= $

Options:

A) 0

B) 1

C) 2

D) $ \infty $

Show Answer

Answer:

Correct Answer: D

Solution:

$ \underset{x\to 1-}{\mathop{\lim }},\frac{1}{|1-x|}=\underset{h\to 0}{\mathop{\lim }},\frac{1}{1-(1-h)}=\infty $ and $ \underset{x\to 1+}{\mathop{\lim }},\frac{1}{|1-x|}=\underset{h\to 0}{\mathop{\lim }},\frac{1}{1+h-1}=\infty $ Hence $ \underset{x\to 1}{\mathop{\lim }}\frac{1}{|1-x|}=\infty . $