Expressing 2*4*6*8*10*etc. mathematically

  • Thread starter Baou
  • Start date
  • #1

Homework Statement

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]

Homework Equations


The Attempt at a Solution

I just don't know how to express 2*4*6*8...etc. mathematically. Help please?
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  • #2
Hint: 2*4*6=23*1*2*3 :wink:
  • #3
Damnit, I knew it'd be something simple... =P Well, thanks for the help!
  • #4
ƒ(x) said:
I believe what you're looking for is...

[tex]\prod[/tex] 2x from 1 to infinity

Why would you think this?:confused:

[tex]\prod_{n=1}^{\infty} 2x=\infty[/tex]
  • #5
gabbagabbahey said:
Why would you think this?:confused:

[tex]\prod_{n=1}^{\infty} 2x=\infty[/tex]

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)