JEE PYQ: Continuity And Differentiability Question 19
Question 19 - 2020 (07 Jan Shift 1)
Let $S$ be the set of points where the function, $f(x) = |2 - |x - 3||$, $x \in \mathbb{R}$, is not differentiable. Then $\sum_{x \in S} f(f(x))$ is equal to ______.