mersenneforum.org  

Go Back   mersenneforum.org > Search Forums

Showing results 1 to 25 of 30
Search took 0.01 seconds.
Search: Posts Made By: toferc
Forum: Miscellaneous Math 2004-11-23, 22:14
Replies: 58
Views: 4,912
Posted By toferc
The cover of the book still has the "The", as...

The cover of the book still has the "The", as does the Library of Congress listing...

</pedant>

Oh, and shaxper... every number you ever do any computing with will be rational.
Forum: Math 2003-08-08, 11:43
Replies: 28
Views: 4,472
Posted By toferc
Consider f(x) = 1.5x + 2. f(0) = 2 (prime) ...

Consider f(x) = 1.5x + 2.
f(0) = 2 (prime)
f(1*2) = 5 (not divisible by 2)
Forum: Miscellaneous Math 2003-08-06, 21:15
Replies: 33
Views: 5,926
Posted By toferc
This seems to deserve proof, so here it is: ...

This seems to deserve proof, so here it is:

Theorem 1: The sum of the decimal digits of an integer x > 0 (sdd(x)) is congruent to x modulo 9.

Proof:
Observe that sdd(1) = 1.
let d(0,k),...
Forum: Miscellaneous Math 2003-08-06, 19:54
Replies: 33
Views: 5,926
Posted By toferc
That's why it's a counterexample :)

That's why it's a counterexample :)
Forum: Miscellaneous Math 2003-08-06, 19:31
Replies: 33
Views: 5,926
Posted By toferc
Counterexample: 2^10*(2^11-1) = 2096128

Counterexample:
2^10*(2^11-1) = 2096128
Forum: Puzzles 2003-08-06, 19:18
Replies: 24
Views: 1,779
Posted By toferc
In that case, $5.03

In that case, $5.03
Forum: Miscellaneous Math 2003-08-06, 19:07
Replies: 33
Views: 5,926
Posted By toferc
[/quote] n = 2: 2^1 * (2^2-1) = 6 n = 3:...

[/quote]

n = 2: 2^1 * (2^2-1) = 6
n = 3: 2^2 * (2^3-1) = 28
n = 5: 2^4 * (2^5-1) = 496

etc.

The definition of a perfect number is that it is equal to the sum of all of its factors. In...
Forum: Puzzles 2003-08-06, 17:55
Replies: 24
Views: 1,779
Posted By toferc
Assuming that the shopkeeper gave change for the...

Assuming that the shopkeeper gave change for the counterfeit $5, all of the other facts are irrelevant. The pirate received $5 worth of goods and cash in exchange for a worthless bill. The...
Forum: Puzzles 2003-08-03, 19:20
Replies: 15
Views: 1,289
Posted By toferc
The whole point of exercises like this is that...

The whole point of exercises like this is that when testing for a rare condition, false positives can (and often do) outnumber true positives, even when the accuracy on a single test is high. The...
Forum: Puzzles 2003-08-03, 19:18
Replies: 15
Views: 1,289
Posted By toferc
You misplaced a decimal. The calculation should...

You misplaced a decimal. The calculation should read
[code:1]
0.1 99
---- x -----
60 100 9.9 9.9...
Forum: Puzzles 2003-08-03, 15:50
Replies: 15
Views: 1,289
Posted By toferc
The statement of the problem was The...

The statement of the problem was


The population of the UK, along with the number of AIDS sufferers in the UK, is exactly the information you need to answer the question.
Forum: Puzzles 2003-07-15, 20:29
Replies: 15
Views: 2,608
Posted By toferc
Just what this forum needed, the 500th "Monty...

Just what this forum needed, the 500th "Monty Hall" flamewar.

I personally have been involved in at least a half-dozen of these.

TravisT has it right, but I'll try to say it another way for...
Forum: Hardware 2003-06-24, 16:51
Replies: 851
Views: 179,639
Posted By toferc
Intel(R) Xeon(TM) CPU 3.06GHz CPU speed:...

Intel(R) Xeon(TM) CPU 3.06GHz
CPU speed: 3056.78 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE, SSE2
L1 cache size: 8 KB
L2 cache size: 512 KB
L1 cache line size: 64 bytes
L2 cache line...
Forum: Lounge 2003-06-20, 17:15
Replies: 2
Views: 1,376
Posted By toferc
Unless I am mistaken, Vincent Edmondson was one...

Unless I am mistaken, Vincent Edmondson was one of the two people responsible for the GIMPS participation at Central Missouri State University, under the account name 'curtisc'.
...
Forum: Puzzles 2003-06-19, 20:27
Replies: 28
Views: 5,276
Posted By toferc
I used cosine rule and double differentiation as...

I used cosine rule and double differentiation as well, though I later thought polar coordinates might be more convenient, or elegant.

Been too busy to post my solution or find a new problem; glad...
Forum: Puzzles 2003-06-09, 23:04
Replies: 28
Views: 5,276
Posted By toferc
Thought I'd allow some time for others before...

Thought I'd allow some time for others before posting the spoiler :)
Forum: Puzzles 2003-06-09, 22:44
Replies: 28
Views: 5,276
Posted By toferc
Clock puzzle

sqrt(7)
Forum: Math 2002-11-23, 03:54
Replies: 5
Views: 2,460
Posted By toferc
Never mind.

Never mind.
Forum: Math 2002-11-04, 12:44
Replies: 7
Views: 1,656
Posted By toferc
Re: Mersenne's on Ulams spiral

This form can be rewritten as 2^k - 1, where k is odd and greater than one, thus these numbers form a subset of the Mersenne numbers. It is known that 2^k - 1 is prime only if k is prime, therefore...
Forum: Software 2002-10-11, 02:49
Replies: 60
Views: 5,935
Posted By toferc
Maybe you know something I don't know... As far...

Maybe you know something I don't know... As far as I know, Intel was founded in 1968, whereas Weitek was founded in 1981.
Forum: PrimeNet 2002-10-09, 05:48
Replies: 33
Views: 6,994
Posted By toferc
OK, I can't resist putting my two cents' worth...

OK, I can't resist putting my two cents' worth in. I've been thinking about this one for some time. I've noticed that 1 P90 CPU year = 1.04*10^15 floating point ops based on the line from the IPS. ...
Forum: PrimeNet 2002-09-26, 04:01
Replies: 228
Views: 19,622
Posted By toferc
Over the years, the Primenet server has proven to...

Over the years, the Primenet server has proven to be both robust and stable. Reimplementing its functionality and maintaining a server are nontrivial tasks, to say the least. I'd like to know if...
Forum: Math 2002-09-26, 02:00
Replies: 17
Views: 4,921
Posted By toferc
Woops :surprised:ops:. I can't believe I said...

Woops :surprised:ops:. I can't believe I said that.

Thank you for clearing that up.

Tofer
Forum: Math 2002-09-15, 03:51
Replies: 13
Views: 3,164
Posted By toferc
jocelynl has got it quite right. It might help...

jocelynl has got it quite right. It might help to look at the GIMPS home page quickie description of the algorithm at

http://www.mersenne.org/math.htm

under "Trial Factoring".

Chris...
Forum: Math 2002-09-14, 18:05
Replies: 17
Views: 4,921
Posted By toferc
The only restriction on the number k is that it...

The only restriction on the number k is that it is a nonnegative integer. For example, M11 = 2^11 - 1 = 2047 has the divisors 1, 23, 87 and 2047.

1 = 2*0*11 + 1 (k=0)
23 = 2*1*11 + 1 (k=1)
87 =...
Showing results 1 to 25 of 30

 
All times are UTC. The time now is 00:39.


Wed Oct 27 00:39:59 UTC 2021 up 95 days, 19:08, 0 users, load averages: 1.20, 1.07, 1.06

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.

This forum has received and complied with 0 (zero) government requests for information.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation.
A copy of the license is included in the FAQ.