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!

A general integral question

  1. Jan 16, 2005 #1
    Ok...now how do I know if a certain integral is solv/integrat-able or not???
    Just by looking at the inside function, how can I tell if the integral can be solved or not??
     
  2. jcsd
  3. Jan 17, 2005 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    How about these steps:

    1.Try conventional methods:part integration,substitutions,partial fraction decompositions,residues theorem.

    2.If it doesn't work,then search for it in "Gradsteyn & Rythzik".

    3.If it's not there,the primitive/anitderivative exists,but it's not expressible through elementary functions.

    Daniel.
     
  4. Jan 17, 2005 #3
    The Wolfram Integrator can also be helpful as a quick reference technique.
     
  5. Jan 17, 2005 #4

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Trust me,that one is useless for nasty integrals.I tried it for about 3 times over the last month and it wouldn't give me anything... :grumpy:


    Daniel.
     
  6. Jan 17, 2005 #5

    Zurtex

    User Avatar
    Science Advisor
    Homework Helper

    Really? Can you give me an example please.
     
  7. Jan 17, 2005 #6

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    I tried an integral that comes up in the Laplace Transform of arctangent

    [tex] \int_{0}^{+\infty} e^{-sx}\arctan x dx [/tex]

    Of course,i asked for the antidifferential,i thought i could apply the theorem of Leibniz & Newton myself...

    Daniel.
     
  8. Jan 17, 2005 #7

    Zurtex

    User Avatar
    Science Advisor
    Homework Helper

    Works fine for me when I enter:

    Code (Text):
    Exp[-s x] ArcTan[x]
     
  9. Jan 17, 2005 #8

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Thenx,Zurtex,there's no wonder i couldn't do it... :tongue2: I misstyped something... :grumpy:
    I like the result,though... :tongue2:

    Daniel.
     
  10. Jan 17, 2005 #9

    Zurtex

    User Avatar
    Science Advisor
    Homework Helper

    Yeah I can't help thinking Wolfram are trying to introduce their own brand of maths :wink:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: A general integral question
Loading...