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Differential equations - backwards problem

  1. Nov 2, 2014 #1
    • OP warned about not including efforts
    1. The problem statement, all variables and given/known data
    If y=y(t) is the solution of the initial value problem

    {
    y'+(2t+1)y=2cos(t)

    y(0)=2

    then

    y''(0)=?

    it is a multiple choice practice problem with choices

    y''(0)=2
    y''(0)=-2
    y''(0)=4
    y''(0)=0
    y''(0)=-4


    2. Relevant equations


    3. The attempt at a solution

    Im really not sure how to go about solving this.

    When I try to solve for y(t) i get a huge mess.
     
  2. jcsd
  3. Nov 2, 2014 #2

    LCKurtz

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  4. Nov 2, 2014 #3

    Simon Bridge

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    Find an expression that has y''(t) in it.
    [edit]... of LCKurtz link: that's interesting: someone in your class?
     
  5. Nov 2, 2014 #4

    LCKurtz

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    ?? Who are you addressing? Me? Not one of my classes. I retired over 10 years ago.
     
  6. Nov 3, 2014 #5

    Ray Vickson

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    Why solve at all? You have ##y'(t) = 2 \cos(t) - (2t +1) y(t)##, so you can get ##y''(t)##.
     
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