Given : f(x)=[ex]+|x2−3x+2| & x∈(−1,3)
∵ex is increasing function ⇒ex∈(1e,e3) for x∈(−1,3)
⇒ex∈(0.36,20.1)
⇒[ex] is not differentiable at 20 integral points.
and |x2−3x+2|=|(x−2)(x−1)| is non differentiale at x=1,2
Clearly, ex is not integer at x=1,2
∴ Total 22 points of non-differentiability.