There are 2 cases. 1. Two sides and an angle opposite to one of the two sides. 2. One side and any two angles.
4 of 8
When to use the first cosine rule
When there is two sides and an angle enclosed between the two sides
5 of 8
When to use the second cosine rule
When you are given a triangle with all 3 sides and no angles
6 of 8
Remember
you only use these rules when a triangle is NOT right angle, you can use normal trig for that
7 of 8
Use this website
you can find all of this at http://www.cimt.plymouth.ac.uk/projects/mepres/step-up/sect4/index.htm. It includes worked answers and questions you can try yourself
8 of 8
Other cards in this set
Card 2
Front
a^2 = b^2 + c^2 - 2bc cosA
Back
The first cosine rule
Card 3
Front
cosA = (b^2 + c^2 - a^2)/ 2bc
Back
Card 4
Front
There are 2 cases. 1. Two sides and an angle opposite to one of the two sides. 2. One side and any two angles.
Back
Card 5
Front
When there is two sides and an angle enclosed between the two sides
Comments
No comments have yet been made