Question

Examine the differentiability of functions in R by drawing the diagram

|cos x|

Answer 1

|cos x| = f(x)

Limit exist and continuous for all x ∈ R clearly, differentiable at `"R" {(2"n" + 1)π/2, "n" ∈ "z"}` Not differentiable at x = `(2"n" + 1) π/2`, n ∈ Z.