# Introduction to Functions

### What is a Function?

### Video

This video from *patrickJMT* explains the notation used to describe functions.

Note: All *patrickJMT* content is available for free at www.youtube.com/user/patrickJMT.

Patrick JMT’s Website: www.patrickjmt.com.

### Notes

These notes from mathcentre explain what a function is. Try the exercises on page 2 to practise what you have learned.

A pdf of this document can be downloaded here.

### The Graph of a Function

### Video

This video from *ProfessorDaveExplains* shows how to plot the graph of linear functions.

Note: All *Professor Dave Explains* content is available for free at www.youtube.com/professordaveexplains.

In this video *patrickJMT* shows how to plot the graph of a quadratic function.

Note: All *patrickJMT* content is available for free at www.youtube.com/user/patrickJMT.

Patrick JMT’s Website: www.patrickjmt.com.

### Notes

These notes from mathcentre go into more detail on plotting the graph of a function.

A pdf of this document can be downloaded here.

### Interactive Exercises

Use GeoGebra graphing calculator below to plot the functions $y=2x-5$, $y=-3x+7$, $y=x^2 + 4$ and $y=-3x^2 + 2x -1$. Adjust some signs/numbers and notice how the graphs change.

Please click here to view this calculator in another window.

### The Domain and Range of a Function

### Video

This video from *Khan Academy* explains how to identify the range and domain of some functions.

Note: All *Khan Academy* content is available for free at www.khanacademy.org.

### Notes

These notes from mathcentre (particularly pages 4-7) explain the range and domain of functions in more detail. Try the exercises included to test your understanding of the range, the domain and functions in general.

A pdf of this document can be downloaded here.