How do you solve 6+2cos(theta)=56+2cos(θ)=5?

1 Answer
Apr 19, 2015

6 + 2 cos x = 5 --> 2cos x = -1 --> cos x = -1/26+2cosx=52cosx=1cosx=12
Trig table gives answer: x_1 = 2pi/3.x1=2π3.
Trig unit circle gives another arc x that has the same cos value:
x_2 = 4pi/3.x2=4π3.
Within the interval (0, 2pi0,2π), there are 2 answers: 2pi/32π3 and 4pi/34π3