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Apr
4
comment Compressing random numbers
One method is to throw away 56 of the possible byte values. The remaining 200 will be random (well, as random as the RNG allows). On average, you'll have to produce $1.28$ bytes to get one you can use.
Apr
4
comment excercise about Linear Algebra
It's guaranteed that $1$ is an eigenvalue, since the matrix is stochastic. Indeed, this particular matrix is doubly-stochastic, which makes finding an eigenvector for the eigenvalue $1$ very simple.
Apr
4
revised Determine conditions for $a,b>0$ such that $f(x)=\sum b^n\sin(a^nx)$ be continuous but nowhere differentiable in $\mathbb{R}$
noted an error
Apr
4
awarded  Revival
Apr
3
comment excercise about Linear Algebra
Indeed. Do you know what a cofactor is? what an adjoint matrix is? how to invert a matrix? This could be a good question, if you would tell us why you are interested in this question, and what you know about it, and how far you can get, and where you get stuck. As is, it's substandard, and I'm voting to close.
Apr
3
comment Easy way to show that $\mathbb{Z}[\sqrt[3]{2}]$ is the ring of integers of $\mathbb{Q}[\sqrt[3]{2}]$
@Andrew, I like Stewart & Tall, also Pollard & Diamond. But if you post a new question, asking for advice, you may get some very useful answers. In fact, you might check to see whether such a question has already been asked on this site.
Apr
3
answered Determine conditions for $a,b>0$ such that $f(x)=\sum b^n\sin(a^nx)$ be continuous but nowhere differentiable in $\mathbb{R}$
Apr
2
comment Hyperbolic cosine
For b), do you know the Maclaurin series for the hyperbolic cosine?
Apr
2
comment 24 Game with $31,41,59,26,53$ and an additional number.
Well, you can't get a positive integer smaller than $1$, so this looks like a winner.
Apr
2
comment How to prove that if $f(z)$ is complex function, then $\Delta Re(f)=0=\Delta Im(f)$?
I take it you are using $\Delta$ for the Laplacian. Are you familiar with the Cauchy-Riemann equations?
Apr
2
comment 24 Game with $31,41,59,26,53$ and an additional number.
$38$ works --- $314+265-358-159-38=24$.
Apr
2
comment Show that $(27!)^6 \equiv 1 \pmod{899}$
lab, my point was that, by doing the entire problem, you left nothing for OP to do. You deprived OP of the joy of figuring out some details for himself (or herself). And if this was a homework problem, you enabled OP to copy your solution and hand it in without him having to think about it or learn anything from it. Is that clearer?
Apr
1
comment Sum the series : $\sum_{n\geq 1} \frac{C(n,0)+C(n,1)+C(n,2)+\cdots+C(n,n)}{P(n,n)}$
chndn, does it help you any to notice that $2^n$ is the total number of subsets of a set of $n$ elements?
Apr
1
comment Proving the multiplicativity of a binary quadratic form
@awllower, no need to delete. I'm annoyed only with myself, for not finding the simpler formula. Your comment is sufficient acknowledgement of similarity.
Apr
1
comment Show that $(27!)^6 \equiv 1 \pmod{899}$
Wasn't me downvoting, but did you give any thought to the comments I left?
Apr
1
revised Mapping intervals exponentially
added 81 characters in body
Mar
27
revised find $n$ so $n/k$ is a $k$th power, $k=2,3,5$.
more informative title
Mar
27
answered find $f(1+i)$ if $\Im[f'(z)]=6x(2x-y), f(0) = 3-2i, f(1) = 6-5i$
Mar
27
answered How to solve this: $\frac{1}{x} - \tan (nx) = \log n $
Mar
27
answered Mapping intervals exponentially