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Math Help - Integration

  1. #1
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    Integration

    HI,
    Integrate int sign 2x-(3-x)^4 dx
    lower limit -2 higher limit 2

    The - sign infront of the bracket, do I work it thru the bracket or work out the power of 4, foil it out, then put thru the negative sign??

    Is this right 2x(x-3)^4 from the above????
    thanks
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  2. #2
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    Re: Integration

    First multiply it out, then multiply by -1: -a^4 is not the same as (-a)^4
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  3. #3
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    Re: Integration

    Making sure I got this right to what you are saying foil it out correct??

    Then work in the negative into that?
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  4. #4
    Super Member TheChaz's Avatar
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    Re: Integration

    Quote Originally Posted by HallsofIvy View Post
    First multiply it out, then multiply by -1: -a^4 is not the same as (-a)^4
    I might add that (3 - x)^4 is the same as (x - 3)^4, which might make things a bit easier.
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  5. #5
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    Re: Integration

    Quote Originally Posted by bradycat View Post
    Making sure I got this right to what you are saying foil it out correct??

    Then work in the negative into that?
    Well, to me "foil" is a thin sheet of metal so I would much prefer to say "multiply"!

    As TheChaz says, \int_{-2}^2 x- (3- x)^4 dx= \int_{-2}^2 x- (x- 3)^4 dx and if you don't want to multiply that, let u= x- 3 so that du= dx and x= u+ 3. When x= -2, u= -5, and when x= 2, u= -1 so that would give
    \int_{-5}^{-1}u+ 3- u^4 du
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  6. #6
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    Re: Integration

    Thank you for all your help. For some reason I was not seeing it. but now I do, thank you again for all the help and explanation.
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