Answer:
See below
Step-by-step explanation:
then f(x)=0 if x<0 and f(x)=x if x≥0.
When x→-∞, f is the constant function zero, therefore . When x→∞, f(x)=x and x grows indefinitely. Thus
f is differentiable if x≠0. If x>0, f'(x)=1 (the derivative of f(x)=x) and if x<0, f'(0)=0 (the derivative of the constant zero). In x=0, the right-hand derivative is 1, but the left-hand derivative is 0, hence f'(0) does not exist,
f'(x)>0 for all x>0. Therefore f(x) is strictly increasing on the inverval (0,∞).