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: A quick integration prob.

  1. May 27, 2007 #1
    How do you integrate [tex]\int secx^{3}tanxdx [/tex]

    I'm substituting [tex]u = tanx [/tex] so [tex]du = sec^2xdx [/tex]


    Now the problem is when I made sec^3x in to sec^2xsecx then I had a secx left over after my substitution. What do I do with this?

    PS: Sorry I'm new at latex and I dont know how to get rid of that {
     
    Last edited: May 27, 2007
  2. jcsd
  3. May 27, 2007 #2

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Try sec(x) = u and substituting. When you differentiate this it may become clearer.
     
  4. May 27, 2007 #3
    Aahh! Thanks tending to infinity man. I got it.

    [tex]\{1/3sec^3x} [\tex]
     
  5. May 27, 2007 #4
    Is there like a post on how to use latex?
     
  6. May 27, 2007 #5

    Kurdt

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If you click on latex images it shows you the code and there is a link below the code to a short PDF with a few tips and small tutorial.

    https://www.physicsforums.com/misc/howtolatex.pdf
     
  7. May 27, 2007 #6

    George Jones

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Delete the \{ and the }.
     
  8. May 27, 2007 #7
    Awsome. Thanks Kurdt and GJ
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook