Prove that the function f given by f(x) = | x - 1| , x€R is not differentiable at x = 1

Prove that the function f given by f(x) = | x - 1| , x€R is not differentiable at x = 1
Prove f(x) = | x - 1| , x€R is not differentiable at x = 1
prove f(x) = | x - 1| is not differentiable at x = 1

#differentiation
#bitwise_tutor