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Thread: Prove.....yeah right :(

  1. October 19th 2009, 04:59 PM #1
    Joel
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    Prove.....yeah right :(

    I am having a brain freeze on this one. Solution would be great.

    Prove:

    sin330cos150 - cos390sin390 = 0


    Thanks so much
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  2. October 19th 2009, 05:23 PM #2
    pickslides
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    Evaluate

    \sin(330)\cos(150) - \cos(390)\sin(390)

    If it is equal to zero then you have proved it.

    I'll kick it off

    \sin(330)\cos(150) - \cos(390)\sin(390)

    \sin(360-30)\cos(180-30) - \cos(360+30)\sin(360+30)

    -\sin(30)\times -\cos(30) - \cos(30)\sin(30)

    you have it from here?
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