Show that $\lim _{x \rightarrow 0} \sin \frac{1}{x}$ does not exist.
Let $x=0+\mathrm{h}$, when $x$ is tends to $0^{+}$
Since $x$ tends to 0 , $h$ will also tend to 0 .
Right Hand Limit(R.H.L.):
$\lim _{x \rightarrow 0^{+}} f(x)$
$=\lim _{x \rightarrow 0^{+}} \sin \frac{1}{x}$
$=\lim _{h \rightarrow 0^{+}} \sin \frac{1}{0+h}$
$=\sin \frac{1}{0}$
$=\sin \infty$
$=\infty$
Let $x=0-h$, when $x$ is tends to $0^{-}$
Since $x$ tends to 0, h will also tend to 0 .
Left Hand Limit(L.H.L.):
$\lim _{x \rightarrow 0^{-}} f(x)$
$=\lim _{x \rightarrow 0^{-}} \sin \frac{1}{x}$
$=\lim _{h \rightarrow 0^{-}} \sin \frac{1}{0-h}$
$=\sin \frac{1}{-0}$
$=-\sin \frac{1}{0}$
$=-\sin \infty$
$=-\infty$
Since,
$\lim _{x \rightarrow 0^{-}} f(x) \neq \lim _{x \rightarrow 0^{+}} f(x)$
$\therefore \lim _{x \rightarrow 0} \sin \frac{1}{x}$ does not exist.