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!

Calculate between [-epsilon,epsilon]

  1. Nov 26, 2009 #1
    i need to integrate

    [tex]-(p(y)f(y)')'=m^2w(y)f(y)[/tex]
    where
    [tex]p(y)=e^{4ky}(1-4ak^2)[/tex] and [tex]w=-4ae^{2y}k\delta(y)[/tex]

    but y between [0,infinity[

    ¿i calculate between [tex]\int^{epsilon}_0????[/tex] or ¿i calculate between [-epsilon,epsilon]?????

    but, what is??

    [tex]\int^{\epsilon}_0(p(y)f(y)')'dy[/tex]

    whit f is not continuous in zero


    the result is
    [tex]f(+\epsilon)=-\frac{m^24akf(0)}{1-4ak^2}[/tex]
     
    Last edited: Nov 26, 2009
  2. jcsd
  3. Nov 26, 2009 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Re: question

    I have no idea what you are talking about. What are yu integrating? If you are talking about the integral above, if it is given as a definite integral, you use whatever limits of integration are given. If it is given as an indefinite integral (anti-derivative) you do not use any limits of integration.

    By the Fundamental Theorem of Calculus, the integral of the derivative of any function is that function:
    [tex]\int^{\epsilon}_0(p(y)f(y)')'dy= p(y)f(y)' [/tex]


    If f is not continuous at zero, then it is not differentiable at zero and the integrand above does not exist at 0.


    Since you haven't actually stated what the problem is, I have no idea whether that is correct or not.
     
  4. Nov 26, 2009 #3
    Re: question

    [tex]f(+\epsilon)=-\frac{m^24akf(0)}{1-4ak^2}[/tex]
    this problem is in eq. (3)-(6)......(10)
    of:
    http://arxiv.org/PS_cache/hep-th/pdf/0311/0311267v3.pdf
     
    Last edited by a moderator: Apr 24, 2017
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Calculate between [-epsilon,epsilon]
Loading...