Question:
If
\[
f(x) =
\begin{cases}
x^2 + 3x + a, & x \le 1 \\
bx + 2, & x > 1
\end{cases}
\]
for \( x \in \mathbb{R} \),
and the function is everywhere differentiable, then:
Show Hint
For differentiability of piecewise functions:
First ensure continuity.
Then match left and right derivatives.
Always check the junction point.