persamaan trigonometri

a cos x + b sin x = k cos (x - t)

k = √(a² + b²)

t = arc tan (b/a)

•

√6 sin x + √2 cos x = 2

sin (+), cos (+) → t di kuadran I

kedua ruas bagi dg √2

√3 sin x + cos x = √2

k = √((√3)² + 1²) = 2

t = arc tan (√3 / 1)

t = 60°

√6 sin x + √2 cos x = 2

√3 sin x + cos x = √2

2 cos (x - 60°) = √2

cos (x - 60°) = 1/2 √2

cos (+) → Kd I dan Kd IV

• Kd I

x - 60° = 45° + k.360°

x = 105° + k.360° ... (1)

• Kd IV

x - 60° = -45° + k.360°

x = 15° + k.360° ... (2)

k bilangan bulat

k = 0 → x = 15° , x = 105°

dan seterusnya

interval 0° ≤ x ≤ 360°

HP = {15° , 105°}