Copyright © University of Cambridge. All rights reserved.

In this diagram $O$ is the centre of a unit circle. Use it to find a trigonometrical relationship between $A$ and $2A$. |

Did you
know ... ?

Trigonometrical expressions can often be derived algebraically or geometrically. In more advanced applications the functions of trigonometry are defined as infinite power series rather than geometric ratios.

Trigonometrical expressions can often be derived algebraically or geometrically. In more advanced applications the functions of trigonometry are defined as infinite power series rather than geometric ratios.