In this post, we establish and use the sine (ambiguous case is required) and cosine rules and the formula for the area of a triangle. This syllabus dot point is a part of the QCE Maths Methods course under the topic Trigonometric Functions 2 and sub-part Cosine and Sine rules, specifically focusing on the sine rule, cosine rule and area of triangle formulas.
- Sine: \frac{a}{sin(A)} = \frac{b}{sin(B)} = \frac{c}{sin(C)}
- Cosine Rule: c^{2} = a^{2} + b^{2} - 2ab cos(C)
- Area of triangle: Area = \frac{1}{2}ab sin(C)
Sine Rule, Cosine Rule and Area of Triangle
Sine Rule Part 1: What does it mean?
Sine Rule Part 2: Proving and using the formula
Cosine Rule Part 1: Proof of the formula
Cosine Rule Part 2: Example of finding the sides
Cosine Rule Part 3: How to tell which rule to use?
