#Help Wolfie
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So I assume Wolfie’e method was
- Prove limit = e
- Show Taylor Polynomial evaluates to e
Maybe use pascal’s triangle to get an infinity term polynomial?
Yes this is exactly wolfies method
i dont see how that woudl help though, which side are you talkinh about, right or left
Left, I’ll look over it more in morning, it’s 11:30 rn
okay okay thanks
What definition of e did Wolfie use?
yeah binomial expansion on the left
i think he solved normally at first
like made left = e and right = e
$\lim_{n\to\infty} \left( 1+\frac{1}{n}\right)^n = \lim_{n\to\infty} \sum_{r=0}^{n} {n \choose r} 1^{n-r} \left( \frac{1}{n} \right)^r$
Yep i think, n!/(n^k) =(n-k)! ?n →∞
(xy)²=(yz)²=(xz)²=xyyzxz=-1
idk if you can swap lim and sum tho
Mm yeah you need to swap, its (n-k)!(1-(k+1)/n)(1-(k+2)/n)*...*1.
You can
You can
$= \sum_{r=0}^{\infty}\lim_{n\to\infty} \frac{n!}{(n-r)!r!} \left( \frac{1}{n^r} \right)$
(xy)²=(yz)²=(xz)²=xyyzxz=-1
yes
$= \lim_{n\to\infty} (1/1! + \frac{n(n-1)}{2!n²} + \frac{n(n-1)(n-2)}{3!n³}+….)$
(xy)²=(yz)²=(xz)²=xyyzxz=-1
(xy)²=(yz)²=(xz)²=xyyzxz=-1
i think that proofed it
this is just harder 💀
but yh it works
so i will credit u for that
thanks @still lynx
@grim cliff has given 1 rep to @still lynx
imma let this thread be
cuz i want a slicker solution if possible so imma go advertise my thread brb
Need solution?
yh
This is quite standard so we can help Wolfie by repeating what we know.
First, we have $(1+1/n)^n=\sum_0^n {n\choose k} (1/n)^k=\sum_0^n {{[n]_k}\over {n^k}}\cdot {1\over {k!}}\le \sum_0^n {1\over {k!}}$ hence $\limsup (1+{1\over n})^n \le a$ where $a$ is RHS.
For the other direction, fix $s\ge 1$ and for $n\ge s$ we have $(1+1/n)^n=\sum_0^n {{[n]_k}\over {n^k}}\cdot {1\over {k!}}\ge \sum_0^s {{[n]_k}\over {n^k}}\cdot {1\over {k!}}$. The RHS here converges to $\sum_0^s {1\over {k!}}$ hence $\liminf (1+1/n)^n \ge \sum_0^s {1\over {k!}}$. This is true for all $s$ hence $\liminf (1+1/n)^n\ge a$.
arohi
Bye,enjoy
Expansion of $(1+\frac{1}{n})^n$ is[ 1 + {n\choose 1}\frac{1}{n} + {n\choose 2}(\frac{1}{n})^2 + ... + {n\choose n}(\frac{1}{n})^n ]A generic term of this series is[{n\choose k}(\frac{1}{n})^k]Expanding this we get[\frac{n!}{k!(n-k)!}(\frac{1}{n})^k]Simplifying it,[\frac{(n-k+1)(n-k+2)(n-k+3)....n}{k!}*(\frac{1}{n})^k]Seeing that the numerator is a polynomial of $\frac{1}{n}$ with degree k, we can simplify it further into[\frac{(1-\frac{k+1}{n})(1-\frac{k+2}{n})(1-\frac{k+3}{n})....1}{k!}]We can call the numerator as $P(\frac{1}{n})$
Expanding it we get $\frac{1}{k!} + \frac{1}{k!}*P(\frac{1}{n})$
We know that n is tending to infinity so $P(\frac{1}{n})$ tending to 0.
Therefore the generic term is $\frac{1}{k!}$
Since there are n terms, and starting from 0. The limit of the sum is[\sum_{k=0}^{\infty}\frac{1}{k!} ]
arohi
literally what i did
Umm what was (n k) again?
The coefficients of the terms in the binomial theorem are in the form $\binom{n}{k}; \binom{n}{k} = \frac{n!}{(n-k)!k!}$
wolfqz
n chooses k
3d pascal triangle 😍
Thanks @grim cliff
@wheat badge has given 1 rep to @grim cliff
Yea this is what I meant
Few remarks. - $P$ depends on $k$ so the notation should be $P_k$.
- the $k$-th term converges to $1/k!$ but, in general, that doesn't mean convergence of the sum since the number of terms tends to infinity. Here it's not a problem since ${{[n]_k}\over {n^k k!}}$ (with value 0 if $n>k$) is majorised by $1/k!$ and $\sum_0^\infty 1/k!$ is finite. Hence we can apply Lebesgue.
arohi
Yet you ask about proving limits...... 
Yeah my bad
You need to sit down and actually know what you know, such discrepancies make people not trust what you're saying
Bro what
If you believe I am a high schooler based on my profile picture, then you are mistaken; that picture is of my sister
No, I just think you're lying about your knowledge given the inconsistency you bring.
Just say you are an engineer 😄
Why should I lie? What would I gain from it?
yoy
stop fighting in this thread
and start giving me better solutions
🥰
cuz the e method is better than binom
Infinite term binomial >>>>
i've recently written a post on my blog for a generalized version of this. the most technical part is a math olympiad-type inequality
vin100
here i assumed knowledge on ratio/root test
tfyneed
cuz all the solutions i got rn, mine is easier and better
context
bro check pinned messages
okay what about it
what would I get
What is your idea?
convert both to e
I feel sorry for the bad UX. I'm not an expert in mobile development. I'm too lazy to provide different HTML tags based on viewport size.
try offering a pdf version of the blog at the end of every edition