jika sin x + cos x = -1/5 tentukan nilai sin x . cos x

jawab

trigonometri

(sin x + cos x )  = -1/5
(sin x + cos x)² = (-1/5)²
1 - 2 sin x cos x = 1/25
2 sin x cos x = 1 - 1/25= 24/45
sijn x cos x = 24/25 :(2)
sin x cos x = 12/15