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: Differentiate, Evaluate Intergral

  1. Sep 26, 2010 #1
    Differentiate:

    (6-xe^x)/(x+e^x)=...


    Evaluate Intergral:

    (2u^5-8u^3+5u^2)du, from lower limit -1 to higher limit 0.
    (i got 10/3 for some reason...)

    (u^7+6u^13)/u^9 du, from lower limit 1 to higher limit 2.
    (n i got 47 for this..)

    I tried these a few times but my answer is still not quite right, so im kinda stuck right now, can any1 help with the answers?
     
    Last edited: Sep 26, 2010
  2. jcsd
  3. Sep 26, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    Differentiation one, just use the quotient rule and the product rule.

    Did not check you intergals yet, but I think your 'dy's should be 'du's instead.
     
  4. Sep 26, 2010 #3
    sorry, i changed it to du.
    For the differentiate, I did use the quotient and product rule, but somehow the answer is wrong.
     
  5. Sep 26, 2010 #4

    rock.freak667

    User Avatar
    Homework Helper

    Could you post your attempt so we can see what, if anything you did wrong?
     
  6. Sep 26, 2010 #5
    [(-e^x-xe^x)(x+e^x)-(1+e^x)(6-xe^x)]/(x+e^x)^2
    is this step right?
     
  7. Sep 26, 2010 #6
    Yes that is correct.
     
  8. Sep 26, 2010 #7
    oh, okay good.then i try to simply it i got [e^x^2+x^2e^x+6e^x+6]/(x+e^x)^2...which is not right...
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook