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May
12
comment How to prove $(\frac{n+1}{e})^n<n!<e(\frac{n+1}{e})^{n+1}$ without integrating method?
Though I guess you could argue that these inequalities are proven by integrating
May
12
answered How to prove $(\frac{n+1}{e})^n<n!<e(\frac{n+1}{e})^{n+1}$ without integrating method?
May
8
revised Expected Value with Variable Probability
added 250 characters in body
May
7
comment Linear Algebra and the determinant of matrix variation
Write $M+\delta M = M(I + M^{-1}\delta M).$
May
7
awarded  Caucus
May
7
comment Expected Value with Variable Probability
I don't understand what you mean? I was just giving faulty reasoning. The nicest proof that I know is as follows: $E[X] = \frac{1}{p} \cdot 1 + \frac{p-1}{p} (E[X] + 1),$ whence $E[X] = \frac{1}{p}.$
May
6
comment limit, low or high bound, convergence for recursive sequence
in response to my previous post, of course you're right - how silly of me.
May
6
comment Expected number of turns
what is the probability that it takes $k$ tries, for $1 \le k \le n$?
May
6
answered Show that an orthogonal group is a $\frac{n(n−1)]}2-$dim. $C^\infty$-Manifold and find its tangent space
May
6
comment Problem related with the zeroes of a polynomial
@learner I posted the proof yesterday
May
6
answered Lebesgue integrable function and square-integrable functions?
May
6
comment Subsequence proof
Did you see my comment above? The idea is that you want $a_n$ to be close to $b$ but far from $c.$ If $|a_n - b| < \epsilon,$ then $|a_n - c| \ge |b-c| - |b-a_n|$ by the triangle inequality. So taking $\epsilon$ as anything less than $|b-c|$ will get you some sort of lower bound on $|a_n - c|.$ He chose $\epsilon < |b-c|/2$ just because it's in the middle
May
6
comment Subsequence proof
ah sorry about that; my reading abilities are lacking. Okay - think about what it means for $a_n$ to not converge to $c.$ This means that there exists $\epsilon$ and an (increasing) sequence $N_k$ such that $|a_{N_k} - c| \ge \epsilon.$ How would you draw this conclusion from what you're given?
May
6
comment Subsequence proof
well, go for contradiction and use the definition of convergence
May
6
comment Induction proof: $\dbinom{2n}{n}=\dfrac{(2n)!}{n!n!}$ is an integer.
this is a little unsatisfying because of that assumption, though
May
6
answered Induction proof: $\dbinom{2n}{n}=\dfrac{(2n)!}{n!n!}$ is an integer.
May
5
comment What does the Heine-Borel Theorem mean?
why is $(a,b)$ necessarily in $I$?
May
5
revised Problem related with the zeroes of a polynomial
Added proof of theorem
May
5
answered Problem related with the zeroes of a polynomial
May
5
revised Expected Value with Variable Probability
added 1 characters in body