Q.
Let $f(x)=\begin{cases}
\sqrt{x^{2}-1}, & x \leq \sqrt{10} \\
(\sqrt{10} x-7), & \sqrt{10} < x < 5 \\
\sin (\pi x), & 5 \leq x < 6 \\
\{x\}, & 6 \leq x \leq 7
\end{cases}$
Then the number of points where $f(x)$ is discontinuous in $[1,7]$ is
[Note: $\{x\}$ denotes fractional part of $x$.]
Continuity and Differentiability
Solution: