A little math help?

Discussion in 'Community Discussion' started by P-Worm, Nov 27, 2006.

  1. P-Worm macrumors 68020

    P-Worm

    Joined:
    Jul 16, 2002
    Location:
    Salt Lake City, UT
    #1
    I am reviewing for a test and came across something that I have never seen before and I was hoping someone could clue me in on what is being talked about.

    I'm supposed to find the general solution of the following equation:

    [​IMG]

    The standard way to do this is to make the derivatives the exponent of r values and then find the roots and plug them into a prefabricated equation. This is their equation for the roots:

    [​IMG]

    I don't get where this came from. What does y^iv mean anyway? Obviously it has something to do with imaginary numbers. :confused:

    Thanks for any help you can provide.

    P-Worm
     
  2. P-Worm thread starter macrumors 68020

    P-Worm

    Joined:
    Jul 16, 2002
    Location:
    Salt Lake City, UT
    #2
    Ha, this always seems to happen when I ask for help. I figure it out right after I ask. Just in case you were wondering, the iv is roman numerals for 4 and that means that it is the fourth derivative of y.

    Blah.

    P-Worm
     
  3. psychofreak Retired

    psychofreak

    Joined:
    May 16, 2006
    Location:
    London
    #3
    You can't post .tiff images, they don't show. People: if you quote, then copy+paste the link.
     
  4. P-Worm thread starter macrumors 68020

    P-Worm

    Joined:
    Jul 16, 2002
    Location:
    Salt Lake City, UT
    #4
    It shows fine for me.

    P-Worm
     
  5. Dandaman macrumors 6502

    Joined:
    Jan 31, 2004
    Location:
    soCal
    #5
    just out of curiousity, why do they put it in roman numerals and not the two? I remember doing stuff like this in my DiffEq class in college a few years ago, but I don't recall why.

    daniel
     
  6. n-abounds macrumors 6502a

    n-abounds

    Joined:
    Mar 6, 2006
    #6
    I'd figure y^iv to mean the fourth derivative of y, just like you said. Although, I don't know what y is so I don't know how they get imaginary numbers...
     
  7. Eraserhead macrumors G4

    Eraserhead

    Joined:
    Nov 3, 2005
    Location:
    UK
    #7
    I'd love to help if I could see the images ;). EDIT: Firefox/Camino won't display them, but Safari will.

    Imaginary numbers could work I suppose, you can differentiate them anyway.

    EDIT 2: I don't think iv necessarily has to be to do with imaginary numbers, 1 has the square roots of 1, -1, but has fourth roots of 1,-1,i,-i (i^2=-1 and -1^2=1)
     

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