C^2 = a^2 b^2 - 2ab cos(c) July 8, 2019 16 32 64 128 C 2 a 2 b 2 2ab cos c C 2 a 2 b 2 2ab cos c proof C 2 a 2 b 2 2ab cos c calculator C 2 a 2 b 2 2ab cdot cos c Prove that c 2 a 2 b 2 2ab cos c C 2 a 2 b 2 2ab cos c make cos c the subject A 2 cos2b b 2 cos2a 2ab cos ab )= c 2 Cosa=1 3 cos(a+b)=-1 3 求a b∈(0 p 2)求cos(a-b)
