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Math Help - using cofunction identities

  1. #1
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    using cofunction identities

    1. cos^2(44) + cos^2(46)

    2. sin2 (79) + sin2 (53) + sin2 (37) + sin2 (11)

    3. Solve the equation for x. Use n as an integer constant.


    thanks!
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  2. #2
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    Quote Originally Posted by mashley View Post
    1. cos^2(44) + cos^2(46)

    2. sin2 (79) + sin2 (53) + sin2 (37) + sin2 (11)

    3. Solve the equation for x. Use n as an integer constant.


    thanks!
    On #1. Note that \cos (44^0)=\cos (90^0-46^0)
    then use the formula \cos (x-y)=\cos x\cos y + \sin x\sin y to simply your answer.

    On #2. A similar strategy can be used like #1. Rewrite some of the angles into sums or differences and simply.

    On #3. When you get down to sin(x)=\frac{-1}{\sqrt{2}}, think about what angles give you such value. It is going to be something "special".
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  3. #3
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    Quote Originally Posted by chabmgph View Post
    On #3. When you get down to sin(x)=\frac{-1}{\sqrt{2}}, think about what angles give you such value. It is going to be something "special".
    I have the same problems as the original poster. I can't seem to get #3 though.

    Help?

    Edit: Nevermind, got it.
    Last edited by TerminatioN; December 9th 2008 at 09:50 PM.
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