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!

Homework Help: Odd integral

  1. Feb 2, 2009 #1
    1. The problem statement, all variables and given/known data

    I want to deal with this int((5+10y^4)dy/(y+2y^5))

    2. Relevant equations

    integration, substitution, partial fractions?

    3. The attempt at a solution

    I tried a bunch of random things. I think it hs to do with substitution because if I make u=y+2y^5, du/dy=1+10y^4 which is strikingly similar to the numerator, so there must be a cancellation. this integral is part of a dif equation, but i cant see to go past this! i know for sure this is the correct set up because i used my calculator to integrate and it solved the differential equation.
  2. jcsd
  3. Feb 2, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper

    Uh, the ratio of those two polynomials is a VERY SIMPLE THING. Can you find it? Factor them.
  4. Feb 2, 2009 #3
    Try this :
    5 + 10y^4 = 4 + 1 + 10y^4

    after you get it, think of a crafty substitution
  5. Feb 2, 2009 #4


    User Avatar
    Science Advisor
    Homework Helper

    Think of a crafty cancellation before you do the crafty substitution.
  6. Feb 3, 2009 #5
    jesus i feel like a complete retard. i hate when i dont get something as obvious.i factored both and cancelled that nasty factor and then everything went smooth, thanks a bunch gentlemen.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook