All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Powered Radicals (Posted on 2025-03-17) Difficulty: 3 of 5
If
(√6 + √2)9   A + B√C
---------- = -------
  (√8)9         D
Then, find the integers values of A, B, C, and D with C square-free.

No Solution Yet Submitted by K Sengupta    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution computer solution | Comment 1 of 7
clc
lhs=(sqrt(6)+sqrt(2))^9/(8192*sqrt(2))
for c=1:50
  f=factor(c)';
  f=groupcounts(f);
  f=mod(f,2);
  f=all(f);  %square free c
  if all(f)
    for a=1:500
      for b=1:500
        for d=1:5000
          if abs((a+b*sqrt(c))/d-lhs)<.0000001
            fprintf('%4d%4d%4d%4d %18.14f %18.14f\n',[a b c d (a+b*sqrt(c))/d  (a+b*sqrt(c))/d-lhs])
          end
        end
      end
    end
  end
end

finds

LHS =   16.5626179236887

  A   B    C  D        RHS                  Diff

 265 153   3  32  16.56261792368869   0.00000000000001
 489 172   7  57  16.56261799128263   0.00000006759394
  13 499   8  86  16.56261785172499  -0.00000007196369
  50 341  27 110  16.56261796493601   0.00000004124733
 265  51  27  32  16.56261792368869   0.00000000000001
 315 392  27 142  16.56261795564084   0.00000003195216
  26 499  32 172  16.56261785172499  -0.00000007196369
 197 380  40 157  16.56261797278961   0.00000004910093
 219 301  42 131  16.56261794061653   0.00000001692785
 262 335  46 153  16.56261793690827   0.00000001321959
 
The first and fifth lines seem to be solutions. Taking the first and verifying to more decimal places:

>> (sqrt(vpa(6))+sqrt(vpa(2)))^9/(sqrt(vpa(8)))^9
ans =
16.562617923688694559678102820325
 
>> (vpa(265)+vpa(153)*sqrt(vpa(3)))/vpa(32)
ans =
16.562617923688694559678102820325
 

  Posted by Charlie on 2025-03-17 09:42:13
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2025 by Animus Pactum Consulting. All rights reserved. Privacy Information