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

Homework Help: Stuck on intergration again

  1. Oct 13, 2004 #1
    i need to intergrate this function
    [tex] \frac{2mdx}{cx^2}[/tex]
    from x to 0
     
  2. jcsd
  3. Oct 13, 2004 #2

    NateTG

    User Avatar
    Science Advisor
    Homework Helper

    If you meant to write:
    [tex] \int_x^{0} \frac{2m}{cx^2}dx[/tex]
    Then you've got the variable of integration in the limits of integration which is ...problematic.
     
  4. Oct 13, 2004 #3

    HallsofIvy

    User Avatar
    Science Advisor

    It is bad practice, although it is often done, to use the same letter to represent the "dummy" variable of integration and as a variable outside the integral (as in one of the limits of integration).

    If you meant
    [tex]\int_x^0\frac{2mdt}{ct^2}[/tex]

    Then rewrite the t2 in the denominator as t-2:
    [tex]\frac{2m}{c}\int_x^0t^{-2}dt[/tex]

    You still have a problem- that's an improper integral which will have serious difficulties at 0! This integral does not exist.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook