Jawabanmu

2014-05-15T16:04:44+07:00
(sin B+cos B)² + (sin B-cos B)² = (sin² B + 2sin B cos B + cos² B) + (sin² B - 2sin B cos B + cos² B) = 2 sin² B + 2 cos² B = 2(sin² B + cos² B) ⇒ menggunakan identitas trigonometri bahwa sin² B + cos² B = 1 ⇒ = 2(1) = 2