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    Solving trigonometric identities.

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    Solve for x:

    a) sin(^2)x=cosx-1

    b) sin2x=cosx

    c) sin2x=2sinx

    © BrainMass Inc. brainmass.com March 4, 2021, 5:39 pm ad1c9bdddf
    https://brainmass.com/math/trigonometry/solving-trigonometric-identities-4990

    Solution Preview

    a) Note that sin(^2)x = 1-cos(^2)x
    So the equation is
    1-cos(^2)x=cosx-1
    cos(^2)x+cosx-2=0
    Let y=cosx
    Then we need to solve y^2+y-2=0
    y=(-1+sqrt(1-(-2*4)))/2 and
    y=(-1-sqrt(1-(-2*4)))/2

    So ...

    Solution Summary

    Trigonometric identities are solved.

    $2.19

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