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Math Help - Definite integral

  1. #1
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    Definite integral

    Hi,

    I am working on the following problem:

    write (4x-3)/(2x+1) in the form A + B/(2x+1) and evaluate the integral of (4x-3)/(2x+1)dx from x=0 to x=2

    I haven't seen a question like this before and don't really know how to solve it... I did some reading around about partial fractions in integration but I am stuck. Any help would be appreciated, thank you.

    Andy
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  2. #2
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    Re: Definite integral

    Quote Originally Posted by andy000 View Post
    Hi,

    I am working on the following problem:

    write (4x-3)/(2x+1) in the form A + B/(2x+1) and evaluate the integral of (4x-3)/(2x+1)dx from x=0 to x=2

    I haven't seen a question like this before and don't really know how to solve it... I did some reading around about partial fractions in integration but I am stuck. Any help would be appreciated, thank you.

    Andy
    This isn't really a partial fractions problem. Those generally involve a product of terms in the denominator.

    What you can do on this problem as you've noted is that it can be rewritten as

    $\dfrac {4x-3}{2x+1} = \dfrac{2(2x+1)-5}{2x+1}=2-\dfrac{7}{2x+1}$

    which is easier to integrate.
    Last edited by romsek; April 20th 2014 at 05:34 AM.
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  3. #3
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    Re: Definite integral

    Oh thanks romsek, I will go from there.

    Cheers
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  4. #4
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    Re: Definite integral

    Oh sorry, should that be -5 instead of -7?
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  5. #5
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    Re: Definite integral

    yes... sorry I answered pre-coffee
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  6. #6
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    Re: Definite integral

    Thanks =)
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