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seen Aug 27 at 14:53

Aug
27
revised Naive proof that $\sum_{n=1}^{N-1}\cos(2\pi\frac{n}{N})=-1$
it's not a dupe
Aug
27
revised Naive proof that $\sum_{n=1}^{N-1}\cos(2\pi\frac{n}{N})=-1$
it's not a dupe
Aug
27
comment Naive proof that $\sum_{n=1}^{N-1}\cos(2\pi\frac{n}{N})=-1$
Not a dupe. DOn't close it. I'm adding details.
Aug
27
asked Naive proof that $\sum_{n=1}^{N-1}\cos(2\pi\frac{n}{N})=-1$
Aug
17
comment A continuously differentiable function with vanishing determinant is non-injective?
My intuition tells me that your intuitive argument will be difficult, mostly because we have no way of knowing how nasty the 'path along the kernel vectors' is.
Aug
2
revised How do you self-study Functional Analysis?
added 4 characters in body
Aug
2
comment Limit of $\arg\min$s
No. ${}{}{}{}{}$
Jul
25
comment How can I determine the function for summing a series of integers?
arrange the numbers in a triangle: $${}$$o$${}$$o o$${}$$o o o$${}$$o o o o$${}$$o o o o o ... How many dots are there in the whole triangle?
Jul
22
comment How do you self-study Functional Analysis?
real analysis in the most introductory-level sense. The italics are what we covered
Jul
22
revised How do you self-study Functional Analysis?
less amb8guity
Jul
22
revised How do you self-study Functional Analysis?
added 10 characters in body
Jul
22
asked How do you self-study Functional Analysis?
Jul
21
comment Exercises in category theory for a non-working mathematican (undergrad)
Martin, your comment essentially amounts to 'it was easy for me so I don't see why you should be having any problems'
Jul
21
comment Do all distributions of R.V.s have a singular part and a continuous part?
I see! I had not properly understood.
Jul
21
accepted Do all distributions of R.V.s have a singular part and a continuous part?
Jul
19
comment Coming up with short “magical” proofs
Thank you so much for not using the word 'mathemagic' in your post
Jul
19
comment A question about the convergence of series.
Theyre all fals.....
Jul
7
accepted What is the difference between a calculus and an algebra?
Jul
7
comment How to approximate large sum of exponential variables
I don't understand your indexing. If $i_1\neq i_2 \neq \dots \neq i_k \neq \dots \neq i_N$ (As I believe you meant?), then how can we be summing over these variables up to $N$? (These are variables which we are summing over which will range from 1 to N; what do you mean by '$\neq$'?) Also, if inside the $\exp$ we have: $$\Large-r_{i_{0k+1}}-r_{i_{1k+1}}-r_{i_{2k+1}}-\dots-r_{i_N}$$, shouldn't $N=n\cdot k+1$ for some $n\in \mathbb{N}$? Sorry if I am misunderstanding something.
Jul
7
revised How to approximate large sum of exponential variables
just formatted & fixed a small typo in the indicies of the summation formula