`cos^2 (x) - 2cos(x) - 1 = 0, [0,pi]` Use a graphing utility to approximate the solutions (to three decimal places) of the equation in the given interval.

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gsarora17 eNotes educator| Certified Educator


using quadratic formula,




Solutions for cosx=1+`sqrt(2)` : None as cos(x) can not be greater than one for real solutions.

cos(x)=1-`sqrt(2)`  , x=arccos(1-`sqrt(2)` )

See the attached graph, Approximate x=2.000

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