Results 1 to 4 of 4

Math Help - Linear ODE problem

  1. #1
    Newbie
    Joined
    Sep 2008
    Posts
    9

    Exclamation Linear ODE problem

    Hi, I am supposed to solve the linear ODE:

    x(dy/dx) + 2y = (sin x) / x , y(2) = 1

    Can anyone help me get started with this? I am at a loss for anything relevant.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by thecelticswin View Post
    Hi, I am supposed to solve the linear ODE:

    x(dy/dx) + 2y = (sin x) / x , y(2) = 1

    Can anyone help me get started with this? I am at a loss for anything relevant.
    do you mean y' = \frac {x^3 - 2y}x ?? ....hey! you changed the question!

    so you have xy' +2y = \frac {\sin x}x

    divide through by x, we get

    y' + \frac 2xy = \frac {\sin x}{x^2}

    now solve using the integrating factor method
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2008
    Posts
    9
    got it, it's even easier if you multiply through by x squared. (integrating factor is just x squared then!) thanks!
    Follow Math Help Forum on Facebook and Google+

  4. #4
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by thecelticswin View Post
    got it, it's even easier if you multiply through by x squared. (integrating factor is just x squared then!) thanks!
    right. i didn't know if you would catch that though, so i wanted to go by the book. sometimes you make such leaps in logic and students get lost and bewildered
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 7
    Last Post: October 10th 2011, 03:06 PM
  2. Dual problem for linear programming problem
    Posted in the Advanced Math Topics Forum
    Replies: 0
    Last Post: March 26th 2011, 04:08 PM
  3. Can anyone help with a linear alg problem
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: February 23rd 2009, 03:58 PM
  4. Linear Map Problem
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: September 17th 2008, 09:44 AM
  5. Replies: 1
    Last Post: February 29th 2008, 09:19 PM

Search Tags


/mathhelpforum @mathhelpforum