If ,
find
where a,b,c are the sides opposite to angles A,B,C in triangle ABC.
please help me...
1. I assume that the a in cos(a) denotes the angle opposite the side a. To avoid some confusion I'll use to denote this angle. Consequently denote the angles opposite the sides b or c.
2. Use a triangle with the side lengthes
a = 7, b = 8, c = 9
3. Use the Cosine rule to determine the cosine values of the corresponding angles.
I've got: