Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Understanding separable ODES

  1. Jan 25, 2015 #1
    I understand how to integrate this: ∫y2dy.

    I dont understand how to integrate this:
    di(t)/dt = i(t)p(t)
    intergrate((di(t)/dt/i(t))*dt = p(t)dt) (see this image: http://i.imgur.com/OdKI309.png)

    how do you perform the intergral on the left, seeing as as it not dt, but di(t)?

  2. jcsd
  3. Jan 25, 2015 #2


    Staff: Mentor

    Can you do this integration? ##\int \frac{du}{u}?##

    BTW, there are no such words in English as "intergrate" and "intergral."
  4. Jan 25, 2015 #3
    Yes I can do that.

    But I do not understand how do integrate (what word do I use?)
    Last edited: Jan 25, 2015
  5. Jan 26, 2015 #4


    Staff: Mentor

    This is essentially the same as what I wrote.
    ##\int \frac{du}{u}## is the same as ##\int \frac{du(t)}{u(t)}##. The only difference is that in the second integral, it is made explicit that u is a function of t.
  6. Jan 26, 2015 #5
    Thank you Mark!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook