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    Solving Trigonometric Identities on an Interval

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    Find all solutions in the interval [0,2pi):
    cos2x + 5cosx = 2

    © BrainMass Inc. brainmass.com October 9, 2019, 7:00 pm ad1c9bdddf
    https://brainmass.com/math/trigonometry/solving-trigonometric-identities-interval-104882

    Solution Preview

    We have the equation cos2x + 5cosx = 2
    We use the identity cos2x=2(cosx)^2-1 here.
    Then the equation becomes
    2(cosx)^2-1+ 5cosx = 2==>2(cosx)^2+5cosx-3=0.
    Observe that 2 x (-3)=-6. Write -6 as product of two ...

    Solution Summary

    Solving Trigonometric Identities on an Interval is investigated.

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