Diketahui tan x = 3 Nilai dari 2 sin x cos x - 1 =......

tan x = y/x =3/1
r = akar (3^2 + 1^2) = akar 10
sin x = y/r = 3/ akar 10
cos x = 1/akar 10
2sin x cos x - 1
= 2 (3/akar 10) (1/akar 10) - 1 = 6/10 -1 = -4/10

Trigonometri

tan A = 3
tan A = y/x = 3/1
r² = x²+y² = 1²+3²
r² = 10
r = √10
.
sin A = y/r = 3/√10
cos A = x/r = 1/√10

nilai 2 sin x cos x - 1 = 2(3/√10)(1/√10) -1
2 sin x cos x -1 =  6/10 - 1
2 sin x cos x - 1= - 4/10
2 sin x cos x = -0,4