Let $f ( x ) = 15 - | x - 10 | ; x \in R$. Then the set of all values of $x$, at which the function $g ( x ) = f ( f ( x ) )$ is not differentiable, is: (1) $\{ 5,10,15 \}$ (2) $\{ 10 \}$ (3) $\{ 10,15 \}$ (4) $\{ 5,10,15,20 \}$
Let $f ( x ) = 15 - | x - 10 | ; x \in R$. Then the set of all values of $x$, at which the function $g ( x ) = f ( f ( x ) )$ is not differentiable, is:\\
(1) $\{ 5,10,15 \}$\\
(2) $\{ 10 \}$\\
(3) $\{ 10,15 \}$\\
(4) $\{ 5,10,15,20 \}$