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General Theory of Functions

What a function is, how functions compose, and the properties that govern real-valued functions — the language every later course speaks.

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General Theory of Functions

Learning Objectives

  • Define a function as a rule that assigns to each element of the domain exactly one element of the codomain.
  • Read and sketch graphs of functions; distinguish a graph from an arbitrary curve.
  • Compose functions and compute the identity function.
  • Determine whether a function is injective, surjective, or bijective.
  • Construct inverse functions for bijections.
  • Classify functions by monotonicity, parity, and boundedness.

About the course

This course develops the general theory of functions from the ground up: the definition, the graph, composition, bijectivity, inverse functions, monotonicity, parity, and boundedness. The linear and quadratic families, studied in subsequent courses, are the first concrete applications of this framework.

Course Units

The Function Concept

The Function Concept

Explore The Function Concept
Composition of Functions

Composition of Functions

Explore Composition of Functions
Properties of Real Functions

Properties of Real Functions

Explore Properties of Real Functions