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Math Help - i have the answer i need the solution

  1. #1
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    i have the answer i need the solution

    Ok, i worked through a problem and got my answer which was wrong, so i checked the solution and i dont understand the last step:

    :integration: 1/8 (1 - cos(2x) - cos^2(2x) +cos^3(2x)dx
    =1/16x - 1/64sin(4x) - 1/48sin^3(2x) + C

    Needless to say, i integrated the same thing and got something different, i tried differentiating the final answer in order to see what i should do, but nothing work for my feeble simian mind.
    Last edited by Nervous; December 3rd 2012 at 12:04 PM.
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  2. #2
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    Re: i have the answer i need the solution

    The first term is x^2/16. I didn't check the other terms. integration x = x^2/2
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    Re: i have the answer i need the solution

    Quote Originally Posted by Nervous View Post
    Ok, i worked through a problem and got my answer which was wrong, so i checked the solution and i dont understand the lasr step:

    :integration: 1/8 (x - cos(x) - cos(2x) +cos^3(2x)dx
    =1/16x - 1/64sin(4x) - 1/48sin^3(2x) + C

    Have a look at this webpage.
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  4. #4
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    Re: i have the answer i need the solution

    Quote Originally Posted by coolge View Post
    The first term is x^2/16. I didn't check the other terms. integration x = x^2/2
    My apologies, that x was meant to be a 1. I'm on my girlfriends tablet, but I'll try to check before I hit enter next time.
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