sebenarnya udah d kerjain tp blm yaki jadi ana mau nanya disini, hhe.............jika cos b = -3/5, berada di kuadran 3, tentukanlah.

cos b = -3/5, sin b = -4/5 ( karena di kuadran 3. a) sin 2b = 2sin b cos b
= 2 (-4/5)(-3/5)
= 24/25
b) cos 2b = cos^2 - sin^2b
= ( -3/5)^2 - ( -4/5)^2
= 9/25 - 16/25
= -7/26
c) tan 2b = (sin 2b) / (cos 2b)
= (24/25) / (-7/25)
= -24/7

Cos b= -3/5,sin B= -4/5 (karena di kuadran 3. a) sin 2b=2 Sin B Cos B
=2 (-4/5)(-3/5)
=24/25 = cos^2
B) Cos^2B - Sin^2B
=(-3/5)^2-(-4/5)^2
Semoga Bermanfaat