1. Not finding help here? Sign up for a free 30min 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!

Yucky integral oh my!

  1. Mar 26, 2007 #1
    The following has been extracted from a larger assignment, the details of which I do not believe are necessary. Anywho, here it is:

    [tex]\frac{1}{\pi}\int\frac{1}{x(\lambda-x)} e^{-(\frac{x-\mu_1}{\lambda-x})^2} e^{-(\frac{x-\mu_2}{x})^2} dx


    things to keep in mind: [tex]\lambda[/tex] as well as [tex]\mu_1[/tex] and [tex]\mu_2[/tex]is only a variable, and the integral ranges from -infiniti to +infiniti.

    What I've tried: distributing out, trying to combine/reduce exponentials (unsuccessful), tried u/du substitution - this seems like it would work, but i couldn't get it to.

    I have completed four semesters of undergraduate calculus, so this isn't new however I'm not quite sure how to go about reducing this. Any tips would be greatly appreciated.
    Last edited: Mar 26, 2007
  2. jcsd
  3. Mar 27, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    The integrand has problems at x=0 and x=\lambda. How would you normally deal with such problems ?
  4. Mar 27, 2007 #3
    A lazy physicist writes:

    Anybody who isn't a mathematician would use Mathematica's the 'Integrator' to solve integrals of this type. (Google 'The Integrator')

    It's important to know how to solve a certain number of integrals by rote and experience. However, I don't see the point of torturing yourself over such complicated integrals as the above- unless they represent some physically interesting phenomenon.
  5. Mar 27, 2007 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    I assume you mean that [itex]\lambda[/itex] as well as [itex]\mu_1[/itex] and [itex]\mu_2[/itex] are NOT variables but are constants.
  6. Mar 28, 2007 #5

    Gib Z

    User Avatar
    Homework Helper

    christianjb, the integrator doesn't understand the different symbols, like the [itex]\lambda[/itex], it can only integrate things that only have x's in it. No way to tell it that those others are constants.

    So either fork out some cash and buy mathematica, or start crying.

    EDIT: No it seems i was wrong, they obviously changed it >.< Well yea your going to have to change the greek letters into ones on your keyboard and convert back.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Yucky integral oh my!
  1. Check my Integration (Replies: 2)