cosine

Question 1

finding unknown angle:

Answer 1

cos A = b ^2 + c ^2 - a ^2 / 2bc

Question 2

finding an unknown side:

Answer 2

a ^2 = b ^2 + c ^2 - 2bc Cos A

Question 3

what’s the ambiguous case?

Answer 3

when angle is obtuse - and we are finding it
when we find it, it will be smaller than an obtuse angle so 180 - angle = actual obtuse angle