Reputation
Top tag
Next privilege 15,000 Rep.
Protect questions
Badges
1 12 31
Newest
 Informed
Impact
~133k people reached

57m
comment Understanding Householder Transformations
OK, I reread it. Is your point that $a = 0.5$, and so why do we mess with calling it the general name $a$? I think you are correct. On the other hand, many other books use $\bf g$ to denote a unit vector. So maybe the writer of this book made a small error, because with the convention that $\bf g$ is a unit vector, you do need an arbitrary $a$. (And it isn't really an error, just unnecessarily complicated.)
1h
comment Understanding Householder Transformations
In one place you have that $\bf g = \bf z - \|\bf z\| \bf e_0$, but later you have $\bf g = \bf z + \|\bf z\| \bf e_0$. Is it possible that this typo is the cause of your confusion?
1d
answered Show that the Lebesgue Stieltjes measure corresponding to $\alpha(x) = \mu((0,x])$ is $\mu$.
1d
comment Positiveness of partial sums of type $ \psi * D_N $
If you plot the first few examples, it is obvious that it is positive. But it also seems to be coincidence that it is positive for small $n$. So my guess is that any proof will be messy.
1d
revised Finding $\sum\limits_{k=0}^n (f(k)g(k))$ (calculus of finite difference)
x->k in the title
Jun
24
revised Arnold Trivium Problem 39
Remark about possible sign error.
Jun
24
comment Arnold Trivium Problem 39
I don't know for sure. But the symbolic Integrate command in Mathematica seemed unable to do the computation.
Jun
24
revised Arnold Trivium Problem 39
Left some parts out of the calculation
Jun
24
comment Arnold Trivium Problem 39
Look at my answer - I already did the numerical calculation. You were off by a sign.
Jun
24
comment Arnold Trivium Problem 39
I also tried $(\vec a, \vec b, \vec c) = (\vec a \times(\vec b\times\vec c))$, and I still seem to be getting $\vec 0$.
Jun
24
revised Arnold Trivium Problem 39
Added more explanation about the unit normal and measure on the surface
Jun
23
comment Arnold Trivium Problem 39
I also tried interpreting it as the vector product $(\vec a,\vec b,\vec c) = ((\vec a\times \vec b)\times \vec c)$, and NIntegrate suggests the answer is $\vec 0$. I bet a modification of the above answer will also work.
Jun
23
revised Arnold Trivium Problem 39
Added sentence at beginning explaining my interpretation.
Jun
23
revised Arnold Trivium Problem 39
Added the proofs at the end
Jun
23
revised Arnold Trivium Problem 39
Add picture and trimmed it
Jun
23
revised Arnold Trivium Problem 39
Add conjectures in last paragraph
Jun
23
answered Arnold Trivium Problem 39
May
12
revised On random rotational fluctuations in $\mathbb{R}^n$
Forgot the 1 in the expansion of exp.
May
12
answered On random rotational fluctuations in $\mathbb{R}^n$
May
11
comment On random rotational fluctuations in $\mathbb{R}^n$
I have an answer, but if you don't know stochastic differential equations, it is unlikely to mean much to you. You at least need to understand the Ito integral from a non-rigorous point of view.