1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    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!

Differentiate part 2

  1. Mar 8, 2008 #1
    1. The problem statement, all variables and given/known data

    RE: F(y)= (1/y[tex]\hat{}2[/tex] - 3/y[tex]\hat{}4[/tex])(y+5y)
    the answer is: F=5+14/y[tex]\hat{}2[/tex]+9/y[tex]\check{}4[/tex]

    3. The attempt at a solution

    F(y)= (f*g)[tex]\acute{}[/tex]

    so, I get (14/y[tex]\hat{}2[/tex] +9/y[tex]\hat{}4[/tex])+5y,
    which is very close to the answer in the book, except that instead of 5y they have the answer as just (14/y[tex]\hat{}2[/tex] +9/y[tex]\hat{}4[/tex])+5
  2. jcsd
  3. Mar 8, 2008 #2
    I cannot clearly read what you did, but you first need to apply the product rule tha is
    let [tex] f(y)=y^{-2}-3y^{-4}, \ \ and \ \ \ g(y)=6y[/tex] so


    or you could merely foil everyghing out and you would end up with:

    [tex]F(y)=6y^{-1}-18y^{-3}[/tex] and then take the derivative of this one.

    However i think that you originally gave us the wrong function, for there is no way you can get the answer you provided us. check it again, for i won't do it for you. Because by just integrating the result you gave us, one cannot get the function you provided.
    Last edited: Mar 8, 2008
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Differentiate part 2
  1. 2 part washer method? (Replies: 2)

  2. Power series (part 2) (Replies: 14)

  3. Laurent series part 2 (Replies: 7)