Question

Jika sudut a memenuhi cos²a + 2 sin (180-a) = sin² (180+a) + 1½, maka sina =

Answer 1

Cos^2 a + 2sin a = (-sin a)^2 + 3/2

(1-sin^2 a) + 2sin a = sin^2 a + 3/2

-2sin^2 a + 2sin a -1/2=0

2sin^2 a -2sin a + 1/2 = 0
Kali 2
4sin^2 a -4sin a + 1 = 0
(2sina - 1)^2 = 0
2sina -1=0
2sina = 1
sin a = 1/2