Question

Nilai dari cos 315° adalah?

Answer 1

Aturan kuadran IV adalah:
cos(360-a) = cos a
Sehingga,
cos(360-45)° = cos 45°
cos 315° = cos 45°
cos 315° = ½ √2

Answer 2

Cos 315 = cos 360 - cos 45
= 1 - 0,5
= 0,5