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Homework Help: Expressing 2*4*6*8*10*etc. mathematically

  1. Mar 26, 2010 #1
    1. The problem statement, all variables and given/known data
    This doesn't seem too hard but I can't figure it out. I'm trying to write out a power series expansion for a function, and after a bit of math I've got: [tex]f\left(x\right) = 1 - \frac32 + \frac98 - \frac{27}{48} + \frac{81}{384}... = 1 - \frac{3^1}2 + \frac{3^2}{2*4} - \frac{3^3}{2*4*6} + \frac{3^4}{2*4*6*8}...[/tex]


    2. Relevant equations
    N/A


    3. The attempt at a solution
    I just don't know how to express 2*4*6*8...etc. mathematically. Help please?
     
  2. jcsd
  3. Mar 26, 2010 #2

    gabbagabbahey

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    Hint: 2*4*6=23*1*2*3 :wink:
     
  4. Mar 26, 2010 #3
    Damnit, I knew it'd be something simple... =P Well, thanks for the help!
     
  5. Mar 26, 2010 #4

    gabbagabbahey

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    Why would you think this?:confused:

    [tex]\prod_{n=1}^{\infty} 2x=\infty[/tex]
     
  6. Mar 26, 2010 #5
    Its late and I'm tired. Dont mind me.

    I thought he was just asking how can you express 2*4*8... (I only read the title)
     
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