16278

Happy Pi day
Happy Pi day everyone!!! The holiday that runs CIRCLES around the other holidays. So gather ROUND and dance in a RING. You can also observe the Pi minute at

richlinda6751

Mar 13

#16278
16277

The Actuary Exam
Hell All (again), Has anyone done the Actuary Exam or works as an Actuary? What did you find difficult about the exam? Do you like working as an Actuary and

opal_rumours

Mar 13

#16277
16276

My Blog
Hello All, I'm starting a math blog aimed at beginners and tutors. Would you please give me some feedback? It is at http://thoughtsonmath.livejournal.com/

opal_rumours

Mar 13

#16276Fetching Sponsored Content...

16275

Re: One-Point Folding
Yes that was the original problem and it's a good problem to consider. But it's a little more difficult than holding two opposite points fixed (along with the

video_ranger

Mar 9

#16275
16274

Re: One-Point Folding
All this time I've been imagining pulling up on just one edge point while somehow the opposite one stayed fixed to the original plane, instead of pulling up on

MorphemeAddict

Mar 7

#16274
16273

Re: One-Point Folding
That's interesting. It looks similar qualitatively - although the actual paper seems to me to be a bit broader or flatter than the graph at the two high points

video_ranger

Mar 6

#16273
16272

Re: One-Point Folding
Ah, I guessed at a result and it looks decent. I put the picture that I made with Octave on my blog page, if anyone wants to take a look.

christopher arthur

Mar 6

#16272
16271

Re: One-Point Folding
Yes - that's a good technique for solving variational problems approximately.

video_ranger

Mar 2

#16271
16270

Re: One-Point Folding
This is tricky since we really have little idea what V is supposed to be. Maybe the idea is to guess with some function of two variables V(s,k) where s is our

christopher arthur

Mar 1

#16270
16269

Re: One-Point Folding
I meant that to signify the square of the the norm - it wasn't very clear: (d^2V/ds^2)^2 = (x''(s))^2 + (y''(s))^2 + (z''(s))^2 where the primes mean second

video_ranger

Feb 28

#16269
16268

Re: One-Point Folding
Yeah, I suppose that the shape reminds me of a kind of cone because of the straight lines from the fold point out to the rim. You define a vector-valued

christopher arthur

Feb 27

#16268
16267

Re: One-Point Folding
To clarify something: consider a flat sheet of paper that becomes a curved surface in three dimensional space when held some way. At each point in the surface

video_ranger

Feb 27

#16267
16266

Re: One-Point Folding
Here's a precise formulation of the problem slightly more faithful to your original statement: Start with a circular sheet of paper of unit radius lying flat

video_ranger

Feb 27

#16266
16265

Re: Can someone back me up? I'm correct and Caltech is wron!
This sort of reminds me of the attitude that I noticed before I gave up on my doctorate in math. I remember telling the student advisor what I thought about

christopher arthur

Feb 24

#16265
16263

Re: One-Point Folding
It would definitely be harder if those two points weren't opposite each other (because of the loss of symmetry). If they were at a relatively shallow angle

video_ranger

Feb 18

#16263Fetching Sponsored Content...

16262

Re: One-Point Folding
That's an interesting way to formalize the problem. I wonder if for some particular arrangements of P and P' the curve would be easier to calculate.

christopher arthur

Feb 17

#16262
16261

Re: One-Point Folding
Here's a summary my thoughts on this problem so far: To simplify things assume the piece of paper is circular in shape (say with radius = 1), with the pencil

video_ranger

Feb 16

#16261
16260

One-Point Folding
Just curious--does anybody have a clue how to write an equation for a surface like the piece of paper in my picture? here's the link to the picture:

christopher arthur

Feb 9

#16260
16256

Conjecture related to ynineteen's problem
Let p be a prime. Let N be the total number of permutations (T) of the p-1 numbers: 1,2,...,p-1 for which the sum: 1*T(1) + 2*T(2) + 3*T(3) + ... +

video_ranger

Jan 29

#16256
16255

Re: My theory is falling apart. Can someone please help?
Do you think that you could write it out with symbols using something like LaTeX and then post it on the web so that we could read it that way?

christopher arthur

Jan 29

#16255
16252

Re: Probablity ?
Actually there are another 36 (at least) 6 digit numbers made with 1,2,3,4,5,6 that are divisible by 7, making a total of 42, so the probability would be

bogaduck

Jan 27

#16252
16251

Re: Probablity ?
1,2,3,4,5,6 can be written 720 different ways, true. 6 of those ways are a 6 figure number divisible by 7, true that means the probability is 6/720 or 1/120

bogaduck

Jan 27

#16251
16250

Probablity ?
I need some help to understand probability, say we have 3 values 1 2 3 , by factorial formula 3x2x1=6 we can write it in 6 different ways, I am looking to find

ynineteen

Jan 26

#16250
16246

Re: Caltech won't get back to me, so I'm posing this question here.
OK. If you say so, I suppose that it could be true...as for me I wouldn't dare contact even my old grad school professors again much less any other

christopher arthur

Jan 19

#16246
16245

Re: 'proof' that sum of all integers is -1/12
Thanks, Ashim Kar and Mark Jones. I suspected something like that, and now I know. It's been so long since I studied series. stevo

MorphemeAddict

Jan 19

#16245Fetching Sponsored Content...

16244

Re: 'proof' that sum of all integers is -1/12
The goof lies in the proof that 1-1+1-1+1..... =1/2, possibly using the formula of GP having a=1 & r = -1 thus 1-1+1-1+1.... ifinite series reduces to 1/(1-r)

ashim_kar123

Jan 19

#16244
16243

Re: 'proof' that sum of all integers is -1/12
For anyone who doesn't want to sit through the video, here's a summary: Definitions: S = 1 + 2 + 3 + ... S1 = 1 - 1 + 1 -1 + ... S2 = 1 - 2 + 3 - 4 + ... Proof

video_ranger

Jan 19

#16243
16240

'proof' that sum of all integers is -1/12
In this video they claim to prove that the sum of all the natural numbers is -1/12. I don't believe it, but I don't know where the error is. Can someone here

MorphemeAddict

Jan 18

#16240
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