NEKG33 Mathematical methods for economists
Chapter 13 : Day 13: Functions
By Lund University
You have been working with functions since sixth grade (or thereabouts). Let's learn what a function really is!
Functions in general
In the first section we study the general concept of a function. A function is a rule that for each element in the domain assigns an element in the codomain. We then focus on real-valued functions of one real variable and look at graphs of such functions. Next, we investigate what happens to the graph of a function when we make changes, such as multiplying the function by a scalar. Finally we look at the definitions of increasing and decreasing functions and the strict versions of these concepts.
Introduction to functions
Natural domain
The graph of a function
The sum, product, difference and ratio of two functions
Shifting graphs
Injective, surjective and bijective functions
Functions in general: Problems
Exercises on functions