April 20th, 2013, 07:48 PM  #1 
Newbie Joined: Apr 2013 Posts: 1 Thanks: 0  Number Theory
Is there a solution to the Diophantine equation (a+b)(c+d)=ab+cd ?

April 20th, 2013, 09:37 PM  #2 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Number Theory
Sure, a = b = c = d = 0. Not sure if there are any nontrivial solutions.

April 20th, 2013, 09:54 PM  #3  
Math Team Joined: Mar 2012 From: India, West Bengal Posts: 3,871 Thanks: 86 Math Focus: Number Theory  Re: Number Theory Quote:
 
April 21st, 2013, 04:50 AM  #4  
Math Team Joined: Apr 2012 Posts: 1,579 Thanks: 22  Re: Number Theory Quote:
 
April 21st, 2013, 06:22 AM  #5 
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Number Theory
One infinite family: a = b = c = 0.

April 21st, 2013, 10:25 AM  #6 
Math Team Joined: Apr 2012 Posts: 1,579 Thanks: 22  Re: Number Theory
Oh, I suddenly realize that this question may be highly relevant to something I was trying to do many years ago. It's gone take some work finding that stuff again in the clutter of my mind. Kinda like trying to remember whether some document you need is buried somewhere in the cluttered basement, cluttered attic or cluttered garage. Depressing, but it may pop to mind. Anyway, in anticipation of remembering what I was trying to do, I would be eager to see ways of dredging up NONtrivial solutions! 
April 21st, 2013, 11:27 AM  #7  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Number Theory Quote:
 
April 21st, 2013, 12:15 PM  #8  
Global Moderator Joined: May 2007 Posts: 6,581 Thanks: 610  Re: Number Theory Quote:
 
April 21st, 2013, 12:27 PM  #9  
Math Team Joined: Apr 2012 Posts: 1,579 Thanks: 22  Re: Number Theory Quote:
 
April 21st, 2013, 12:39 PM  #10  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Number Theory Quote:
 

Tags 
number, theory 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
number theory  gaussrelatz  Math Events  19  November 29th, 2012 01:29 AM 
Graph theory and number theory  proglote  Number Theory  3  October 30th, 2011 04:20 PM 
number theory  sivela  Number Theory  3  May 10th, 2010 07:43 AM 
number theory  vinodannu  Number Theory  1  August 17th, 2008 04:20 PM 
Number Theory  sxm6719  Number Theory  2  December 31st, 1969 04:00 PM 