How do you find the general solutions for sin 2 theta = cos thetasin2θ=cosθ?

1 Answer
Jun 3, 2018

pi/6; pi/2; (5pi)/6; (3pi)/2π6;π2;5π6;3π2 + (2kpi)(2kπ)

Explanation:

sin 2t - cos t = 0
2sint.cos t - cos t = 0
cos t(2sin t - 1) = 0
Either factor should be zero.
a. cos t = 0
Unit circle give 2 solutions
t = pi/2t=π2, and t = (3pi)/2t=3π2
b. 2sin t - 1 = 0 --> sin t = 1/2sint=12
Trig table and unit circle give:
t = pi/6t=π6, and t = (5pi)/6t=5π6
Fro general answer, add 2kpi2kπ