Global and local maximum in the case f(x) is differentiable and non-differentiable.

[HB281]

Ive been given a coursework for a module ive been forced to take this year, im struggling to understand most of the questions.

One particular one is as follows:

Let f : R -> R.

Explain global and local maximum of f(x) in the cases that f(x) is differentiable and non-differentiable.

I dont know where to even begin answering this

 

[BigBeachBanana]

Start with their definitions.
What does it mean for a function to be differential non-differentiable?
What is global max vs local max?
What does being differential have to do with the maximum of a function?