Trig
posted by Kay on .
Solve the following interval
0<_ (less than or equal to)0(Theta)<2pi:
1. sin0(theta) + sin2 0(theta) = 0
2. 2cos^20 (theta) + cos0 (theta) 1 = 0

sinӨ + sin2Ө = 0
recall that sin2Ө = 2sinӨcosӨ
so sinӨ + sin2Ө = 0
sinӨ + 2sinӨcosӨ = 0
sinӨ(1+2cosӨ)=0
sinӨ = 0 or 2cosӨ = 1
sinӨ = 0 or or cosӨ = 1/2
Ө = 0,pi,2pi or Ө=2pi/3,4pi/3
in degrees: 0,180,360,120,240