Posted by **raj** on Monday, October 29, 2007 at 10:50am.

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

- math -
**drwls**, Monday, October 29, 2007 at 12:16pm
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.

- math -
**Reiny**, Monday, October 29, 2007 at 1:45pm
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

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