Using the sine and cosine rules together (AQA GCSE Further Maths): Flashcards

Cosine rule

Cosine rule

Sine rule

Sine rule

Three

$a^2 = b^2 + c^2 - 2bc \cos A$

$\cos A = \frac{b^2 + c^2 - a^2}{2bc}$

$\frac{\sin A}{a} = \frac{\sin B}{b} = \frac{\sin C}{c}$

$\frac{1}{2}ab \sin C$

Clockwise from North

Not independent; third angle determined by first two

Ambiguous case - two possible solutions

Draw a diagram

Rounding too early causes significant errors