Mathematicslimits-continuity-and-differentiability2021medium
Let the functions f : R → R and g : R → R be defined as :
f(x) = \left\{ {\matrix{
{x + 2,} & {x < 0} \cr
{{x^2},} & {x \ge 0} \cr
} } \right. and
g(x) = \left\{ {\matrix{
{{x^3},} & {x < 1} \cr
{3x - 2,} & {x \ge 1} \cr
} } \right.
Then, the number of points in R where (fog) (x) is NOT differentiable is equal to :