SOLUTION: Solve the equation on the interval [0,2pi] for sin^2 theta-cos theta=4. What is the solution set?

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Question 627085: Solve the equation on the interval [0,2pi] for sin^2 theta-cos theta=4. What is the solution set?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Solve the equation on the interval [0,2pi] for
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sin^2 theta-cos theta = 4
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Substitute for sin^2
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1-cos^2(x) - cos(x) = 4
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Rearrange
cos^2+cos+3 = 0
cos = [-1 +- sqrt(1-4*3)]/2
cos = [-1 +- sqrt(-11)]/2
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Note: The cos values are complex numbers.
No Real Number solution for theta.
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Cheers,
Stan H.