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Reduction of order from 2nd to 1st

  1. Oct 3, 2011 #1
    I have been given the equation:
    y'' + y' - 2y = 0
    and asked:
    " Express the equation as a 1st-order system. Solve the system using matrix methods."

    I thought in order to reduce an equation you needed one solution to it already. I tried using the general solution but it got messy.

    Someone please help?
  2. jcsd
  3. Oct 3, 2011 #2

    D H

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    Staff Emeritus
    Science Advisor

    Hint #1: Make the substitution y'=z. This should give you a first order ODE involving two variables (as opposed to a second order system of one variable).

    Hint #2: Express this first order system in matrix form.

    Hint #3: This is almost certainly in your text and in your lecture notes.
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