Question: Determine all values of x, \(-10<x<10\) such that the indicated function is not differentiable

(a) \(f\left( x \right)=x|x|\)

(b) \(f\left( x \right)=|{{x}^{2}}-1|\)

(c) \(f\left( x \right)={{\left( 1-{{x}^{2/3}} \right)}^{3/2}}\)