SOLUTION: Use inverse trigonometric functions to find the solutions of the equation that are in the interval [0, 2π).You may enter an exact answer or round your solutions to four decima

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Question 816327: Use inverse trigonometric functions to find the solutions of the equation that are in the interval [0, 2π).You may enter an exact answer or round your solutions to four decimal places (this is best for this problem). (Enter your 4 answers in a comma separated list.)
cos(x)(11cos(x) + 7) = 3
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
cos(x)(11cos(x) + 7) = 3
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11cos^2(x) + 7cos(x) - 3 = 0
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Use Quadratic Formula to get:
cos(x) = [-7 + sqrt(49-4*11*-3)]/22 = 0.2933
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arccos(0.2933) = 1.2731
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OR
cos(x) = [-7 - sqrt(49-4*11*-3)]/22 = -0.9297
arccos(-.9297) = 2.7544
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Cheers,
Stan H
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