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Apr
17
revised Proof that $\lim \frac{a_n}{1+a_n^2} = 0 \implies \lim a_n = 0$
deleted 2 characters in body; edited title
Apr
17
revised Sum of digits of $11\dots 11^2$ where $11\dots 11$ is a 1992 digit number with all digits $1$
edited tags
Apr
17
comment Simplifying Sum
@Guest: Using binomial theorem. It is a standard technique. You don't need to know RHS for it.
Apr
16
comment Simplifying Sum
Without the algebra precalculus tag, the left side is $$\int_{0}^{1} (1-x)^n x^m \text{d}x$$ which is a Beta integral...
Apr
14
awarded  Notable Question
Apr
1
awarded  Popular Question
Mar
29
comment Diophantine system of two equations with four variables
+1: More accessible to a 9th grader, than complex numbers I suppose.
Mar
29
answered Diophantine system of two equations with four variables
Mar
28
revised Counting the number of integers $i$ such that $\sigma(i)$ is even.
edited tags
Mar
28
revised Counting the number of integers $i$ such that $\sigma(i)$ is even.
edited tags
Mar
28
comment Counting the number of integers $i$ such that $\sigma(i)$ is even.
Is this an algorithm problem? Assuming it is, retagging as elementary-number-theory.
Mar
26
comment Calculation of limit without stirling approximation
A previous answer of mine proves this in a completely elementary fashion: math.stackexchange.com/a/131084/1102. Falls right out of Proposition E.
Mar
26
comment Can the sum of reciprocals of a set without density converge?
Convergence implies density is zero. See: math.stackexchange.com/questions/5932/…
Mar
26
revised Proof : Limit of a sequence
edited tags
Mar
19
comment Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
+1: Nice.......
Mar
19
revised Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
more informative title.
Mar
19
comment Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
This is not pedantry. I don't think this is as trivial as you seem to be implying. Unless you have a proof, you are just handwaving. Anyway, you are free not to elaborate, and I am free to leave the downvote intact.
Mar
19
revised Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
edited tags
Mar
19
comment Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
Please take at least a day or two before accepting an answer. In this case, the accepted answer is incomplete.
Mar
19
comment Aproximation of $a_n$ where $a_{n+1}=a_n+\sqrt {a_n}$
The heuristic is only a first step. Making it rigorous is the hard part. -1 till there is a proof. Sorry.