Misal diketahui mulai 6 sin x + 12 cos x =7 dan 6 sin x -3 cos x =2 .nilai 2 tan x = ?

6 sin x + 12 cos x = 7
6 sin x - 3 cos x = 2
------------------------------ (-)
15 cos x = 5
cos x = 1/3

6 sin x - 3(1/3) = 2
6 sin x - 1 = 2
sin x = 1/2

↓
2 tan x
= 2 sin x / cos x
= 2 . (1/2)/(1/3)
= 2 . 3/2
= 3