1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

How to integrate e^x cos(x) using parts?

  1. May 31, 2007 #1
    Is it possible to intergrate

    e^x (cosx)

    i wondered because i tried to intergrate it by parts, but ended up going round in circles.

    I wondered because i had this question and im stuck on how to do it :)

    http://img505.imageshack.us/img505/320/frfbc8.png [Broken]
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Jun 1, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    Sure it's possible. Just integrate by parts twice. You will get back to where you started - but if you call the integral I, then you will get I=somthing-I. So I=something/2. Not circular. On the other hand the question you posted is done more directly with deMoivre. cos(x)+j*sin(x)=e^(j*x).
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook