Question

Mohon dijawab.
Jika cos41, 41derajat = 3/4 maka cos 3,59derajat sama dengan...
A. 1/8akar2 (3+akar7)
B. 1/8akar2 (3-akar7)
C. 1/8akar2 (akar7-3)
D. 1/8 (3+akar7)
E. 1/8(3-akar7)

Answer 1

Jawab A
cos 41,41 = 3/4
sin 41.41 = √{1- (3/4)²} = 1/4 √7

cos 3,59 = cos (45 - 41,41)
cos 3,59= cos 45 cos 41,41 + sin 45 sin 41,41
cos 3,59 = 1/2 √2 . (3/4)  + 1/2 √2 ( 1/4 √7)
cos 3,59 =1/8 √2 ( 3)  + 1/8√2 ( √7)
cos 3,59 = 1/8 √2 ( 3 +√7)