persamaan trigonometri

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

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- sin x + cos x = 1

sin (-) , cos (+) → kuadran IV

k cos (x - t) = 1

k = √(a² + b²)

k = √((-1)² + 1²) = √2

t = arc tan (b/a)

t = arc tan (-1/1)

t = arc tan (-1)

t = 315° kuadran IV

- sin x + cos x = 1

k cos (x - t) = 1

√2 cos (x - 315°) = 1

cos (x - 315°) = 1/√2

x - 315° = 45° + k.360°

x = k.360° ... (1)

cos (x - 315°) = 1/√2

x - 315° = -45° + k.360°

x = 270° + k.360° ... (2)

k bilangan bulat

misal interval 0°≤ x ≤ 360°

k = 0 → x = 0° atau x = 270°

dan seterusnya

HP = {0° , 270° , 360°}