Bantuin dong No 15, 16, 17 Makasih...

Materi : Trigonometri
Bahasan : Koordinat Kutub dan Kartesius

Langkah - langkah dan Jawaban :
15. (-12, 12)
r = √(-12)² + (12)²
r = √288 ⇒ 12√2
cos α = x / r
cos α = (- 12) / 12√2 (Rasionalkan)
cos α = (-1/2)√2
cos α = 135°
⇒ (12√2, 135°)

16. (14, 30°)
x = r cos α
x = 14 cos 30°
x = 14 (1/2)√3
x = 7√3
y = r sin α
y = 14 sin 30°
y = 14 (1/2)
y = 7
⇒ (7√3, 7)

17. (6, 6√3)
r = √(6²) + (6√3)²
r = √144 ⇒ 12
cos α = x / r
cos α = 6 / 12
cos α = 1/2
cos α = 60°
⇒ (12, 60°)