What are some sums of infinite series that are = to 'e'?

In summary, the conversation discusses various infinite series that equal 'e' and asks for recommendations on where to find more information on the subject. Some series mentioned include ##\displaystyle e=\sum_{n\geq 0}f(n)## and ##\displaystyle e=\sum_{n\geq 0}f(n)##, where ##\displaystyle f(n)=\left\{\begin{matrix}e & \text{if } n=0 \\ 0 & \text{if } n\neq 0\end{matrix}\right.##. The conversation also explores the idea of finding infinite series that sum to other numbers, such as pi or 42, and suggests multiplying them
  • #1
mesa
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We all know about the sum of the infinite series,

1 + 1/1! + 1/2! + 1/3! + ... to 1/inf! = e

What other series do we have that are equal to 'e'?
 
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  • #3
Panphobia said:

I honestly don't know how you guys find so much more on Wikipedia than I do...

Either way, that is an excellent list of 'infinite series', are there any others?
 
  • #4
mesa said:
I honestly don't know how you guys find so much more on Wikipedia than I do...

Either way, that is an excellent list of 'infinite series', are there any others?
I like $$e=\sum_{n\geq 0}f(n),$$ where ##\displaystyle f(n)=\left\{\begin{matrix}e & \text{if } n=0 \\ 0 & \text{if } n\neq 0\end{matrix}\right.##. :tongue:
 
  • #5
Mandelbroth said:
I like $$e=\sum_{n\geq 0}f(n),$$ where ##\displaystyle f(n)=\left\{\begin{matrix}e & \text{if } n=0 \\ 0 & \text{if } n\neq 0\end{matrix}\right.##. :tongue:

That's different... :)
 
  • #6
Mandelbroth said:
I like $$e=\sum_{n\geq 0}f(n),$$ where ##\displaystyle f(n)=\left\{\begin{matrix}e & \text{if } n=0 \\ 0 & \text{if } n\neq 0\end{matrix}\right.##. :tongue:
Personally, I prefer $$e=\sum_{n\geq 0}f(n),$$ where ##\displaystyle f(n)=\left\{\begin{matrix}e & \text{if } n=1 \\ 0 & \text{if } n\neq 1\end{matrix}\right.##
 
  • #7
So is this all of them, as in if someone found something else outside of these then it's new to maths?
 
  • #8
mesa said:
So is this all of them, as in if someone found something else outside of these then it's new to maths?
Do you honestly think we know all of mathematics?

I'd venture to guess that there are at least SOME (*cough*SUM*cough*) other representations out there. :tongue:
 
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  • #9
Mandelbroth said:
Do you honestly think we know all of mathematics?...

Nope, just trying to see if someone else has more information. Do you have recommendations on where to find out more on the subject such as books, websites, etc.?
 
  • #10
mesa said:
Nope, just trying to see if someone else has more information. Do you have recommendations on where to find out more on the subject such as books, websites, etc.?
That list is not exhaustive. There is, as far as I know, not much interest in simply finding new infinite series that add up to 'e,' except perhaps if a new series converges much more rapidly than a previously known series.
 
  • #11
Jorriss said:
That list is not exhaustive. There is, as far as I know, not much interest in simply finding new infinite series that add up to 'e,' except perhaps if a new series converges much more rapidly than a previously known series.

I would imagine that would be valuable from a computing standpoint. What's the current record, 10 trillion decimal places or something to that effect?
 
  • #12
mesa said:
I would imagine that would be valuable from a computing standpoint. What's the current record, 10 trillion decimal places or something to that effect?
In what sense valuable? I do not believe there is much interest in finding more decimal places to e beyond the novelty of having found new decimals - though someone more knowledgeable can certainly correct me.
 
  • #13
mesa said:
Do you have recommendations on where to find out more on the subject such as books, websites, etc.?

Why not concentrate on finding infinite series that sum to [itex] 1 [/itex] and then multiply them by [itex] e [/itex]? That would let you find series that sum to [itex] \pi [/itex] or [itex] 42 [/itex] or whatever.
 
  • #14
Jorriss said:
In what sense valuable? I do not believe there is much interest in finding more decimal places to e beyond the novelty of having found new decimals - though someone more knowledgeable can certainly correct me.


I find it remarkable we live in a time where we know a 1,000,000,000,000+ decimal places of 'e'. Euler and the like would probably be in awe of such an accomplishment.

Also I think figuring out new ways of calculating 'e' is important since it could help us gain new insight and lead to better maths in the future (much like it has proven to do so in the past).
 
  • #15
Stephen Tashi said:
Why not concentrate on finding infinite series that sum to [itex] 1 [/itex] and then multiply them by [itex] e [/itex]? That would let you find series that sum to [itex] \pi [/itex] or [itex] 42 [/itex] or whatever.

Brilliant!

$$e=e*2\sum_{n= 2}^{∞}(n-1)/((2)n!)$$
$$42=42*2\sum_{n= 2}^{∞}(n-1)/((2)n!)$$
$$pi=pi*2\sum_{n= 2}^{∞}(n-1)/((2)n!)$$
$$llama=llama*2\sum_{n= 2}^{∞}(n-1)/((2)n!)$$

Yes I 'cheated' with the 2 multiplier but so far I have only been able to derive an infinite sum to 1/2 and finals are calling...
These things fun!
 

1. What is 'e' and why is it important in mathematics?

'e' is a mathematical constant that is approximately equal to 2.71828. It is the base of the natural logarithm and is important in many mathematical and scientific calculations, such as compound interest, population growth, and radioactive decay.

2. What is an infinite series?

An infinite series is a sum of an infinite number of terms. Each term in the series is added to the previous term, and the sum of all the terms is the infinite series.

3. How is 'e' related to infinite series?

'e' can be expressed as an infinite series, specifically the sum of 1/n!, where n ranges from 0 to infinity. This series converges to 'e' and is known as the Taylor series for 'e'.

4. Can you give an example of an infinite series that equals 'e'?

One example is the infinite series 1 + 1/1! + 1/2! + 1/3! + ... which is equal to 'e'.

5. Are there any other sums of infinite series that equal 'e'?

Yes, there are many other infinite series that converge to 'e', such as 1 + 1/2 + 1/4 + 1/8 + ... and 2 - 1 + 1/2 - 1/3 + 1/4 - 1/5 + ... These series are derived from different mathematical concepts, such as geometric and harmonic series.

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