Can someone please give me step by step how to with the cosine law?

I need a step by step how to for using the cosine law in both cases (with 3 sides, or 2 sides and the surrounded angle) examples would be appreciated.Can someone please give me step by step how to with the cosine law?
1. Capitalized alphabets are usually referred as the point where there's the angle. 2. Small alphabets usually express as the lengths opposite of the point when there's an angle.





2 sides and the surrounded angle (this is to find length):


c^2 = a^2 + b^2 - 2ab (Cos C)


c = squareroot {a^2 + b^2 - 2ab (Cos C)}





3 sides (find the angle opposite of the respective length)


Cos C = [a^2 + b^2 - c^2]/2ab


C = Cos^-1 {[a^2 + b^2 - c^2]/2ab}Can someone please give me step by step how to with the cosine law?
theres 3 formulas you can use:


a^2= b^2 + c^2 - 2bc (cosA)


b^2 = a^2 + c^2- 2ac (cosB)


c^2 = a^2 + b^2 - 2ab (cosC)





^2 = squared


and the parenthesis means multiply





just plug in what youre given and solve it algebraically for what you have missing.


for example if youre given b and c and angle A then use the first formula.


if you have all sides and no angles use any formula and solve for the angle, remember to do the inverse, cos-1 on your calculator.





good luck %26lt;3 adriana