Q. If $f(x) = |x - 2|and\ g(x) = f\left( f(x) \right)$, then for $x > 20,\ g^{'}(x)$ is equal to
A) $- 1$
B) 0
C) 1
D) 2
Explanation
(c)
$f\left( f(x) \right) = f(|x - 2)$
$= ||x - 2| - 2|$
$= x - 4\ \ \ (\because x > 20)$
$\Rightarrow \ g(x) = x - 4$
$\therefore g^{'}(x) = 1$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.