This post is part of the HSC Maths Extension 1 syllabus, under the topic Further Trig focusing on solving t-formulae questions. The t-formulae are the following:

if we let:

t = tan( \frac{x}{2})Then we can express:

sin(x) = \frac{2t}{1+t^2} cos(x) = \frac{1-t^2}{1+t^2} tan(x) = \frac{2t}{1-t^2}

### Solving Questions Using the t-formulae

In this video, you will learn to use the t-formulae to solve trig equations.

### More Examples of Solving Equations with t-formulae

##### Part 1:

##### Part 2:

Want to learn more? Check out more of our HSC Extension Maths resources here!