Question

Hasil cos alfa = sekalian caranya ya , makasih

Answer 1

8²+6²-2(8)(6) cos(180-a) = 4²+2²-2(4)(2) cos a
100 - 96(-cos a) = 20 - 16(cos a)
100 - 20 = -96(cos a) - 16(cos a)
80 = 112 cos a
cos a = 80/112 = 5/7