Help With Expansion of f(x) Function!

  • Context: Undergrad 
  • Thread starter Thread starter NEWO
  • Start date Start date
  • Tags Tags
    Expansion Function
Click For Summary

Discussion Overview

The discussion revolves around the expansion of the function f(x) = exp(x)/(exp(x)-1)^2. Participants explore various methods for expanding the function, including series expansions and Taylor series, while clarifying the nature of the expansion sought.

Discussion Character

  • Homework-related
  • Exploratory
  • Mathematical reasoning

Main Points Raised

  • One participant seeks help with expanding the function, indicating difficulty in understanding the process.
  • Another participant questions the meaning of "expand," suggesting that it could involve multiplying out the denominator.
  • A participant asserts that a series expansion exists for the function, prompting further inquiry from the original poster.
  • Suggestions are made to compute the Taylor series or manipulate the function by adding and subtracting terms.
  • One participant recalls the Taylor series for exp(x) and applies it to derive the needed expansion, indicating a resolution to their query.

Areas of Agreement / Disagreement

Participants generally agree that a series expansion exists for the function, but there are different approaches suggested for obtaining it. The discussion reflects a mix of uncertainty and exploration of methods without a definitive consensus on the best approach.

Contextual Notes

Some participants reference the Taylor series and specific manipulations of the function, but the discussion does not resolve the details of these methods or their applicability in all contexts.

Who May Find This Useful

Readers interested in function expansion, series expansions, or those seeking assistance with similar mathematical problems may find this discussion relevant.

NEWO
Messages
93
Reaction score
0
help! expansion

hi, I am trying to expand a function and can't seem to do it, if some one can tell me how to do it i would appreciate it trmendously. The following is the function;

f(x)=exp(x)/(exp(x)-1)^2

im guessing it is something simple, but i just can't grasp it.

Thank you for your time

newo
 
Physics news on Phys.org
What do you mean by expand? Do you mean just multiplying out the denominator?

[tex]f(x) = \frac{e^x}{e^{2x} - 2e^x + 1}[/tex]
 
im just seing if there is a series expansion for the above, if not then it doesn't matter.
 
Of course there exists a series expansion of that function, why do you ask?
 
coz i need it, I can't find it!

by the way i have looked for it but my books are limited and I am not at uni at the mo so can't go to the library.
 
Well, compute the first few terms of the Taylor series about some point, then! :smile:
 
How about adding and subtracting 1 from the numerator ?
 
Well, it might be simpler to write:
[tex]f(x)=\frac{d}{dx}\frac{1}{1-e^{x}}[/tex]
and expand the denominator in the differentiand to the degree desired.
 
its ok after looking through some stuff and asking my dad, lol I suddenly remembered about the taylor series of exp(x)=1+x+x^2/2! etc... and if x=c/a and if a>>c we can negate x^2 term due to being much smaller than the x term hence,

exp(x)---> 1+x

and I get what I needed anyway from that so that's great thanks anyway
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 36 ·
2
Replies
36
Views
6K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
6K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K