Question
Show that $\lim _{x \rightarrow 4} \frac{|x-4|}{x-4}$ does not exist.

Answer

Let $x-4=n \Rightarrow$ As $x \rightarrow 4, n \rightarrow 0$
$
\begin{aligned}
\therefore \text { L.H.L } & =\lim _{n \rightarrow 0-} \frac{|n|}{n}=\lim _{n \rightarrow 0-} \frac{-n}{n} \\
& =\lim _{n \rightarrow 0-}(-1)=-1
\end{aligned}
$
$\begin{aligned} \text { R.H.L } & =\lim _{n \rightarrow 0+} \frac{|n|}{n}=\lim _{n \rightarrow 0+} \frac{n}{n} \\ & =\lim _{n \rightarrow 0+}(1)=1\end{aligned}$
Since L.H.L $\neq$ R.H.L 
$\lim _{x \rightarrow 4} \frac{|x-4|}{x-4}$ does not exist.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free