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-   -   Partial Fraction (https://www.askmehelpdesk.com/showthread.php?t=49668)

  • Dec 20, 2006, 11:16 AM
    Big Toosie
    Partial Fraction
    I have work this problem (1/P)dP/dt=b+aP to the point that I am confused on the partial fraction part

    (1/P)dP/dt=b+aP

    1/dt=bP+aP^2/dp this where Iam stuck to finish the equation I must do partial fraction.:eek:
  • Dec 20, 2006, 12:34 PM
    asterisk_man
    Can you state the original problem? What are you trying to solve for?

    Is your dP/dt implying a derivative?
    I assume it must because otherwise your left hand side the d/d and the P/P would cancel to give 1/t
    But then I'm still confused because you're taking the derivative of P with respect to t... but you don't have any t anywhere.

    More info on the problem will help us help you... unless someone comes by and tells me I'm an idiot... which is possible!
  • Dec 20, 2006, 03:20 PM
    Big Toosie
    The Original Problem is

    1/P dP/dt=b+aP <<Edit by capuchin, you didnt mean to put the ^2 here right?

    Now multiplying P to both sides gives

    dP/dt=bP+aP^2

    Now dividing by dP to get dt on one and dP on one side

    1/dt=(bP+aP^2)/dp

    This where I am suck I have to use Partial fraction to finish the problem.
  • Dec 20, 2006, 06:12 PM
    Capuchin
    Why do you move the dp over?

    Why don't you integrate wrt t?
  • Dec 20, 2006, 07:04 PM
    asterisk_man
    but that's where I'm confused. Since there isn't any t in the equation bP+aP^2 is a constant so just replace it with C and you've got dP/dt=C and the integral is P=Ct=(bP+aP^2)t
    then I guess you can solve for P if you'd like

    P/(P(b+aP))=t
    1/(b+aP)=t
    b+aP=t
    aP=t-b
    P=(t-b)/a

    but I'm just saying this because I'm not sure where else to go with this
  • Dec 9, 2008, 06:55 PM
    malijfar
    Gerald and Michelle went on a 24-mile bike ride. By lunchtime, they had ridden 5/8 of the total distance. How many miles did they have left to ride after lunch?
  • Dec 10, 2008, 03:45 PM
    galactus
    This is a logistic equation.



    Separate and take partial fractions:





    Integrate:



    Multiply both sides by b and use law of logs



    Now, can you finish?

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