Search found 22 matches

by Darrell88
Sat Dec 24, 2011 4:00 pm UTC
Forum: Mathematics
Topic: Multiple Choice Problem
Replies: 9
Views: 1844

Re: Multiple Choice Problem

Wow whose bumping all those old threads !!! :shock:
by Darrell88
Fri Dec 23, 2011 5:27 pm UTC
Forum: Mathematics
Topic: Math Books
Replies: 378
Views: 240428

Re: Math Books

Hi everybody. I was wondering if someone had a good suggestion for a book on advanced number theory . Also I'm looking for a good book on intuitionism. I've tried Intuitionism , An Introduction by Heyting but I hate the Galileo " Discourses and Mathematical Demonstrations Relating to Two New Sc...
by Darrell88
Wed Dec 21, 2011 6:10 pm UTC
Forum: Mathematics
Topic: Odd factors of 2^n-1?
Replies: 5
Views: 2008

Re: Odd factors of 2^n-1?

It's pretty hard without modular arithmetic ... but once you know Euler's theorem and Euler's totient function the proof becomes pretty trivial ( 2 is always coprime to odd numbers so if n is an odd number : 2^{\phi(n)} \equiv 1 \ (mod \ n) which means that 2^{\phi(n)} - 1 is...
by Darrell88
Thu Dec 08, 2011 8:26 pm UTC
Forum: Mathematics
Topic: Convergence Tests For Series
Replies: 29
Views: 5757

Convergence Tests For Series

Hi everybody. I was just wondering if there is a theorem or logical reasoning why convergence tests for series will always be inconclusive for certain series ... Thanks for your help.
by Darrell88
Thu Dec 01, 2011 4:46 pm UTC
Forum: Mathematics
Topic: Requesting Inequalities and Tips to Solving Them
Replies: 9
Views: 2076

Re: Requesting Inequalities and Tips to Solving Them

If you want some really advanced notions of inequalities, I advise you to read "Handbook of Means and Their Inequalities" by Bullen. It's a bit bulky but very informative ...
by Darrell88
Thu Dec 01, 2011 3:17 pm UTC
Forum: Mathematics
Topic: can you crack it?
Replies: 13
Views: 8084

Re: can you crack it?

I thought it was an Ascii art or some phonetic lingo rather than a real cryptographic problem ... I tried ascii arting it and got something like an S or a 5 or an inverted Z but the other half was bullsh*t though ... so maybe it's just a crypto then :oops:
by Darrell88
Fri Nov 18, 2011 3:23 pm UTC
Forum: Science
Topic: Well, this could change things (neutrinos)
Replies: 289
Views: 39030

Re: Well, this could change things (neutrinos)

Hmmm I have a noob question: How do they measure the time of departure and time of arrival of these neutrinos ???
by Darrell88
Sat Nov 12, 2011 1:27 pm UTC
Forum: Logic Puzzles
Topic: The surprise exam paradox
Replies: 217
Views: 62073

Re: The surprise exam paradox

Still don't understand why this isn't classed simply as an inconsistent theory.
by Darrell88
Fri Sep 23, 2011 8:05 am UTC
Forum: Science
Topic: Well, this could change things (neutrinos)
Replies: 289
Views: 39030

Re: Well, this could change things

Thought it was from a school lab, but if it's from the CERN then there's a high chance it could be true. But I really hope that they made a mistake cos it could bring down 100 years of physics ....
by Darrell88
Sat Sep 17, 2011 7:11 pm UTC
Forum: Mathematics
Topic: Proof By Induction
Replies: 13
Views: 1816

Re: Proof By Induction

Thanks everybody for your posts and helping me clear this doubt. But I still think that I'll avoid using induction because I could be sacrificing real mathematical understanding for convenience. :D By the way the book was Discrete Mathematics by Rosen and the quote :"It is extremely important t...
by Darrell88
Thu Sep 15, 2011 6:27 pm UTC
Forum: Mathematics
Topic: Proof By Induction
Replies: 13
Views: 1816

Proof By Induction

Hi everybody. I've been reading a few books about mathematical reasoning and I came across an interesting statement in one of the books but I can't remember which one, which said something like "induction can only be used to prove a result obtained some other way but can't be used to discover n...
by Darrell88
Mon May 30, 2011 5:00 pm UTC
Forum: Mathematics
Topic: alternative mathematics
Replies: 128
Views: 12555

Re: alternative mathematics

kumarevo wrote:The existing angles of 180 degrees, if you specify items may be quadrilateral, pentagon...

task. prove ,to be a real number , result of division of two integers (a fraction)


With the commas it's clearer.
This is becoming more linguist and hieroglyphical than a mathematical :D
by Darrell88
Wed May 25, 2011 2:01 pm UTC
Forum: Mathematics
Topic: Cutting a polygon into triangles (Polygon triangulation)
Replies: 2
Views: 1742

Re: Cutting a polygon into triangles (Polygon triangulation

Is it what you meant Tirian? 2.png Let N n be the number of ways of triangularising a n-polygon. If I fix a side and draw a triangle to any vertex ( excluding the fixed side) , I always get two polygons on the left and on the right of my triangle whose sum of sides= n+1. Because the number of ways o...
by Darrell88
Wed May 25, 2011 10:12 am UTC
Forum: Mathematics
Topic: Cutting a polygon into triangles (Polygon triangulation)
Replies: 2
Views: 1742

Cutting a polygon into triangles (Polygon triangulation)

I was reading about Catalan numbers in a book and it said that the number of ways of cutting a n side convex polygon into triangles is the n-2 th Catalan number e.g for a pentagon there's 5 ways and for a hexagon there's 14 ways. http://upload.wikimedia.org/wikipedia/commons/3/36/Catalan_number_poly...
by Darrell88
Sun May 22, 2011 12:33 pm UTC
Forum: Mathematics
Topic: alternative mathematics
Replies: 128
Views: 12555

Re: alternative mathematics

Natural axiom: Natural along. Point is the beginning (end) longer natural. Natural along with 2 points. Natural along the base length. Natural longer connecting points. There is always the first point (A). MS.A-Natural along . Point . What does Natural along mean? Give us a clear and simple example...
by Darrell88
Thu May 19, 2011 8:50 am UTC
Forum: Mathematics
Topic: Solving PDE's
Replies: 9
Views: 1455

Re: Solving PDE's

Ok last question. If y = x− ct and z = x+ct and u(x,t)=v(y(x,t),z(x,t)) then using the Chain rule is the following eqn correct ?: \frac{\delta u}{\delta t}= \frac{\delta v}{\delta y}\frac{\delta y}{\delta t}+ \frac{\delta v}{\delta z}\frac{\delta z}{\delta t} And also I'm not too sure how to apply ...
by Darrell88
Wed May 18, 2011 5:31 pm UTC
Forum: Mathematics
Topic: Solving PDE's
Replies: 9
Views: 1455

Re: Solving PDE's

Ok last question. If y = x− ct and z = x+ct and u(x,t)=v(y(x,t),z(x,t)) then using the Chain rule is the following eqn correct ?: \frac{\partial u}{\partial t}= \frac{\partial v}{\partial y}\frac{\partial y}{\partial t}+ \frac{\partial v}{\partial z}\frac{\partial z}{\partial t} And also I'm not too...
by Darrell88
Tue May 17, 2011 8:23 pm UTC
Forum: Mathematics
Topic: Solving PDE's
Replies: 9
Views: 1455

Solving PDE's

Hi everybody. Just wondering if someone can help me out on some simple PDE's. Btw I'm just a math student and we're supposed to know how to solve some easy PDE's this semester but all the tutorials I've come across on the internet contain a lot of Physics and Engineering jargon. So I have to solve t...
by Darrell88
Mon May 02, 2011 12:24 pm UTC
Forum: Mathematics
Topic: Math Olympiad Problems
Replies: 8
Views: 1866

Re: Math Olympiad Problems

I did 3 by a long and rigourous method , by breaking up the digits into sequences For 7: 7\times10^{2n+2} , n\geq0 , where n represents the nth term For 1's: (\sum_{i=0}^{n}10^{n+1+i}) - 10^{n+1} = 10^{n+1}(\frac{10^{n+1}-10}{9}) For 2: 2\times10^{n+1} For 8's: (8\sum_{i=0}^{n}10...
by Darrell88
Fri Apr 22, 2011 10:32 am UTC
Forum: Mathematics
Topic: Tarski's World
Replies: 3
Views: 1593

Re: Tarski's World

Thanks a lot. Now it seems to make sense :D !!!
by Darrell88
Tue Apr 19, 2011 8:19 am UTC
Forum: Mathematics
Topic: Tarski's World
Replies: 3
Views: 1593

Tarski's World

Hi everybody. I'll be doing FOL next year so I'm reading a book on Tarski's World but I don't have the software. So if someone could please give me a brief description of what "Tarski's World" is all about and how it works , I'll be grateful :D
by Darrell88
Mon Apr 04, 2011 12:43 pm UTC
Forum: Logic Puzzles
Topic: The surprise exam paradox
Replies: 217
Views: 62073

Re: The surprise exam paradox

I think that the subtlety here is predicting that an exam will take place and predicting that an exam won't take place. Let's assume on Thursday evening the students predict that the exam will take place on Friday and stop they their reasoning there. On Friday morning they tell their professor "...

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