1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Integrating factor confusion

  1. Sep 19, 2009 #1
    1. The problem statement, all variables and given/known data
    Solving this differential equation
    ty' + 2y = t^2 - t + 1

    2. Relevant equations
    Its linear so i set it up in linear form
    y' + y(2/t) = t - 1 +1/t

    3. The attempt at a solution

    the integrating factor (u) = e ^ integral (ydt) = e^ integral (2dt/t)...
    Here's the question, my book says u = t^2, and i just can't figure out how e ^ integral (2dt/t) is t^2

    Its probably some stupid thing that i'm getting stuck on, thanks.
    I know how to do this afterwards, i just can't for the life of god figure out why u = t^2
  2. jcsd
  3. Sep 19, 2009 #2
    [tex]u = e^{\int\frac{2dt}{t}} = e^{2\ln t} = (e^{\ln t})^2[/tex]
  4. Sep 19, 2009 #3
    oh wow i thought u could bring the 2 out front.... thanks for clearing that up
  5. Sep 19, 2009 #4
    Thanks Bohrok, I thought that was were is was coming from also but was having trouble typing it out.

    Last edited: Sep 19, 2009
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Integrating factor confusion
  1. Integrating factor (Replies: 12)

  2. Integrating factors (Replies: 6)

  3. Factoring an Integral (Replies: 8)

  4. Integrating Factor (Replies: 4)

  5. Integrating factor (Replies: 5)