34,899 reputation
13265
bio website zakuski.utsa.edu/~jagy
location Berkeley, CA
age 57
visits member for 2 years, 11 months
seen 1 hour ago

I put an email address here and intended it to be visible. In case it is not, search with my last name at http://www.ams.org/cml/

See me at http://mathoverflow.net/users/3324/will-jagy

and http://zakuski.utsa.edu/~jagy/ and

http://zakuski.math.utsa.edu/~kap/forms.html and

http://arxiv.org/find/math/1/au:+Jagy_W/0/1/0/all/0/1

If people would include the source of a given problem as part of the process of posting a question, life would be a little easier.


1h
comment Divisor of $3^{2n+1}+61$
Jyrki, good.... I believe, from Euler's version of Fermat's Little Theorem, we can add $272 = \phi(289)$ to the exponent of $3$ and get $17^2$ again, same for adding $2 \cdot 272,$ and so on
2h
comment Divisor of $3^{2n+1}+61$
@JyrkiLahtonen, no source is given for this. My guess, pending detail, is that this is false for occasional large $n$ but finding them will be difficult.
3h
comment Divisor of $3^{2n+1}+61$
For a single value of $n,$ or for all values of $n,$ or what?
5h
comment History Question re Euler's Constant $\gamma$
Well, his pdf is at the wikipedia article, see pages 555-556.
5h
comment History Question re Euler's Constant $\gamma$
Lagarias says: At that time constants were often named after a person who had done the labor of computing them to the most digits.....In the current era, which credits the mathematical contributions, it seems most appropriate to name the constant after Euler alone.
6h
answered How to create alternating series with happening every two terms
7h
comment Proof: Show there is set of $n+1$ points in $\mathbb{R}^n$ such that distance between any two distinct points is $1$?
@Klick, start small. See if you can rotate the line $x+y=0$ to the $x$-axis in the plane, then try $x+y+z=0$ to the $xy$-plane in $\mathbb R^3.$ Must be rotations, it is not good enough to have just any linear transformation.
8h
answered Proof: Show there is set of $n+1$ points in $\mathbb{R}^n$ such that distance between any two distinct points is $1$?
8h
comment Proof: Show there is set of $n+1$ points in $\mathbb{R}^n$ such that distance between any two distinct points is $1$?
If I gave you an explicit vector $v$ in $\mathbb R^{n+1},$ not necessarily of unit length, would you be able to find the matrix describing the (simplest) rotation that takes $v$ to a (positive) multiple of $(0,0,0, \ldots, 1)?$
1d
comment Soccer Team- Venn Diagram
Tried a couple of times, I do not believe your conditions are consistent, even if we allow fractional players. The problem is the large number of regions (out of 15 inside the ellipses) that must be assigned the number $0.$
1d
answered Soccer Team- Venn Diagram
1d
comment Soccer Team- Venn Diagram
I recommend you draw several copies of a Venn diagram for four sets, carefully label, and see how it goes. I found three nice versions for four sets at en.wikipedia.org/wiki/… , first is three circles and a banana, next is four ellipses, finally two rectangles, a circle and a peanut, by someone named Edwards. Oh, also, you cannot make a correct Venn diagram with four perfect circles; they show that also.
1d
comment Nice parameterization of $x^2 + y^2 - kx^2y^2 =1$
Noe that $$ x^4 - k x^2 y^2 + y^4 = 1 $$ is similar and a little better behaved, for example rotation by $45^\circ$ gives you one of the same with a different $k$ value
2d
comment Series and Sequences: Given $S_n = 3 n^2 - 11 n$, find $T_n$ and hence show that the series is arithmetic.
What is a Tn???
2d
comment Successively longer sums of consecutive Fibonacci numbers: pattern?
If you rewrite every one of these results, on the right-hand side, as the appropriate $$ A F_n + B L_n, $$ you should get an understandable pattern in how $A,B$ change depending on the number of terms summed. I think you can avoid rational coefficients (as opposed to integers only) by switching to $$ A F_{n-1} + B L_{n-1}. $$
2d
comment Generalised Pythagorean Theorem?
should be $+ 2 Re(\bar{a}b)$
Apr
22
revised Existence of perfect square between the sum of the first $n$ and $n + 1$ prime numbers
added 335 characters in body
Apr
22
revised Projection on cone of non-negative definite matrices
added 88 characters in body
Apr
22
answered Projection on cone of non-negative definite matrices
Apr
22
comment Projection on cone of non-negative definite matrices
Well, it appears you want references 17 and 20. The language suggests that there are advantages to different methods for different investigations, and this method is best for this article. I'm looking through a standard book, Horn and Johnson, maybe they have something