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Homework Help: O.D.E. Complementary and Particular Solution

  1. Mar 13, 2006 #1
    Not exactly homework, but it is a problem I'm having...

    Im given an ode that reads:
    y"-2y'-3y = 6;
    [itex]y_c = C_1 * /exp^-x + C_2 * /exp^3x[/itex]
    [itex]y_p[/itex] is -2

    y(0) = 3
    y'(0) = 11

    Now I am tasked to find what [itex]C_1[/itex] and [itex]C_2[/itex] are.

    I know that y(x) = [itex]y_c + y_p[/itex]
    so:
    y = [itex]C_1 * /exp^-x + C_2 * /exp^3x[/itex] - 2
    and
    y' = [itex]-C_1 * /exp^-x + 3 * C_2 * /exp^3x[/itex]

    The book defines the answers as:
    [itex]C_1[/itex] = 1 and [itex]C_2[/itex] = 4

    Yet when I work it out, Ive gotten [itex]C_1[/itex] = 2 and [itex]C_2[/itex] = 3.

    What am I doing wrong?

    NOTE: I hope I did the itex right... my computer isnt showing them... :biggrin:
     
  2. jcsd
  3. Mar 13, 2006 #2
    Nevermind... I got it to work. I had a simple Aritmatic Error
     
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