Question

Bila tgA=-3/4 maka nilai dari 3cosA+2sinA / cosA-4sinA =
a.1/8
b.2/8
c.3/8
d.4.8
e.5/8

Answer 1

Tan A = -3/4 = de/sa => ada 2 kemungkinan
bisa di kuadran 2 atau kuadran 4
mi = √(3^2 + 4^2) = √25 = 5
sin A = de/mi = 3/5
cos A = sa/mi = 4/5

kuadran 2
(3cosA+2sinA)/(cosA-4sinA)
= (3 . -4/5 + 2 . 3/5) / (-4/5 - 4 . 3/5)
= (-6/5) / (-16/5)
= 6/16 = 3/8

kuadran 4
(3cosA+2sinA)/(cosA-4sinA)
= (3 . 4/5 + 2 . -3/5) / (4/5 - 4 . -3/5)
= (6/15) / (16/15)
= 6/16 = 3/8
ternyata sama saja jawabannya