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Homework Help: Simple looking 2nD ODE, with 2 sols, 0 and 3, confused on what to do now!

  1. Feb 16, 2006 #1
    Hello everyone, I have time again to do more math so here i am!
    I'm confused on what they want me to do here, I found A and B but they arn't pretty and i dind't even think they are right. Here is the problem, it has 2 inital conditions, both y(x) no y'(x) which also confused me.
    ind y as a function of t if
    y'' - 3y' = 0,
    y(0) = 9, y(1) = 7 .
    y(t) =

    http://img51.imageshack.us/img51/566/lastscan0ei.jpg [Broken]

    THanks! any help would be great!
     
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Feb 16, 2006 #2
    There is a mistake in your line [tex]7=Be^{3t}+A[/tex]. Can you see it?


    EDIT: As so emphatically :wink: pointed out below, that is your mistake.
     
    Last edited: Feb 16, 2006
  4. Feb 16, 2006 #3

    HallsofIvy

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    Science Advisor

    A and B are CONSTANTS!! In y(1)= 7, you didn't set t= 1.
     
  5. Feb 16, 2006 #4
    Ahh thank you everyone, I friggin' got it:
    http://cwcsrv11.cwc.psu.edu/webwork2_files/tmp/equations/cf/6cde53ce8c93c51ddfe1e2f50b5e411.png [Broken]
     
    Last edited by a moderator: May 2, 2017
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