math
posted by raj .
Solve the following equations giving any roots in terms of pi in the .......?
interval 2pi ≤ 0 ≤ 2pi.
a) 2cos²Θ + sin²Θ = 0
b) 2cos²Θ + sin²Θ = 1
c) 2cos²Θ + sin²Θ = 2

First convert cos^2 theta to 1  sin^2 theta. Then treat sin^2 as a new variable x and solve for that using quadratic equation procedures.

I will do the last one for you
2cos²Θ + sin²Θ = 2
2cos²Θ + 1  cos²Θ = 2
cos²Θ = 1
cosΘ = ±1
in degrees, Θ = 0º or 180º or 360º
in radians: Θ = 0 pi or 2pi