Leeds University Library
Our website is changing

The Library website is changing. Our new website will go live at the start of semester 2.


Trigonometry is the branch of mathematics that explores the relationships between angles and side lengths in triangles.

The trigonometric functions (eg sin, cos, tan) are used in many different areas of mathematics, including many applied topics, and so it's important you understand what they represent and how to work with them. 

In these videos you'll learn:

  • how to use basic trigonometric functions to find side lengths and angles in triangles
  • rules and identities involving these functions
  • how to convert between degrees and radians.

You can navigate through the videos by clicking on the three-bar menu icon in the top left of the video and selecting the one you would like to watch from the playlist.

Playlist consists of:
  1. Pythagoras Theorem
  2. Trig ratios 1
  3. Trig ratios 2
  4. Trig identities 1
  5. Trig identities 2
  6. Trig identities 3
  7. Converting angles: deg to rad
  8. Converting angles: rad to deg
  9. Solving trig equations 1
  10. Solving trig equations 2
  11. Solving trig equations 3
  12. Solving trig equations 4
  13. Solving trig equations 5
  14. Cosine Rule 1
  15. Cosine Rule 2
  16. Sine Rule