Before You Watch


This video is designed to refresh your memory of trigonometry and what it means.

It uses algebra to represent the various sides and angles of the triangle. So, if you’re not confident with the concept of algebra and how symbols represent certain values, watch Introduction to Algebra first, then come back.

The Video

Want to save this content? Download Resource Sheet

Now What?

The next step in your trigonometry journey is to watch Components of Vectors. This video demonstrates a specific application of trigonometry used in science and engineering, as well as giving sample questions that you’re likely to come across at university and beyond.

But When I am Going to Use This

Right-angled triangles are common in construction, surveying and the application discussed in the Components of Vectors video, where things like forces, or movements, are broken down into perpendicular components. However, trigonometry also extends to non-right angled triangles through applications like the sine rule and the cosine rule, and to calculating the areas of triangles.

Moving beyond triangles, trigonometry is critical to the study of waves, such as radio waves. This is very important in fields such as wireless communication and quantum physics: for instance, mobile phone technology would be impossible without a method of breaking down a signal into a series of sines and cosines known as Fourier Analysis. Your GPS device also uses trigonometry to help you navigate using satellites.

Other Links

Maths Is Fun has a great page summarising the trigonometric ratios and includes several different applets to help you visualise and understand the basics. It also has other pages dealing with more advanced trigonometry subjects to develop your understanding.

The Mathspace page on trigonometry is well laid out with a variety of instructive videos, applets and quizzes. It also has apps for iPad, iPhone, Android and Windows Phone. It does require you to create a login; however, using these resources is free.

GeoGebra is a mathematics app that works on a wide variety of platforms, including tablets, and in a web browser. It is used to create great tools for teaching and learning. The link here is an example of a GeoGebra ‘program’ that helps demonstrate how trigonometric ratios stay constant, no matter how the triangle shrinks and expands.

The following link is to a simple animation demonstrating the creation of the graph of the sine function using the unit circle. It also has attached the source code for the creation of the animation. For people who have a natural orientation towards computer programming (which is a huge application of mathematics) this may help understand the nature of trigonometry.

The Khan Academy has a comprehensive set of video tutorials covering a large range of mathematical and other concepts, as well as questions to test your knowledge. This link takes you to the chapter covering basic trigonometry, and continues onto more advanced trigonometric concepts.

Patrick JMT (Just Maths Tutorials) has a comprehensive set of video tutorials covering a large range of mathematical concepts. This video covers the trigonometric ratios and solves a variety of problems using these ratios.