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: Integration help

  1. Dec 9, 2008 #1


    (integral sign)= (x+1/x+2)+3
  2. jcsd
  3. Dec 9, 2008 #2


    User Avatar
    Gold Member

    If (x+1/x+2) is one term (not sure you have written it correctly), ((x+1/x+2)^2)/2 +3x

    You raise the term to the next power and divide the whole thing by that power.
  4. Dec 9, 2008 #3


    User Avatar
    Science Advisor
    Homework Helper

    Dead wrong. Differentiate that and use the chain rule. It doesn't work. You have to integrate each term separately. Integrate x, 1/x, 2 and 3 and add the results.
  5. Dec 9, 2008 #4


    Staff: Mentor

    What exactly is the problem? "(integral sign) = <whatever>" makes no sense to me. Is this the problem?
    [tex]\int (\frac{x + 1}{x + 3} + 3)dx[/tex]

    Or is this it?
    [tex]\int (x + 1/x + 2 + 3)dx[/tex]
    I suspect that this is not what you meant, although Dick interpreted what you wrote that way.

    If the first integral is the one you meant, you'll need to divide (x + 1) by (x + 2), which will give you 1 + (some number)/(x + 2).
  6. Dec 9, 2008 #5
    to thread starter :
    if it is the first integral that Mark is referring to, you should most probably get 4x-ln(x+2)
  7. Dec 9, 2008 #6


    User Avatar
    Science Advisor
    Homework Helper

    I'm not sure giving the answer is really the way we give help here, is it?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook