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

Home > Numbers
Year by Year 2 (Posted on 2022-03-02) Difficulty: 3 of 5
Consider N = 20222022

Reading from left to right, determine:
(1) The last 4 digits of N.
(2) The first 4 digits of N.

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution solution (spoiler) Comment 1 of 1
Probable intended solution:

(1)

p=1;
for i=1:2022
   p=mod(p*2022,10000); 
end
disp(p)

yields the last four digits as 1584.

TI-84 plus CE calculator:

1 STO>P
For(I,1,2022)
(P*2022) STO>P
remainder(P,10000)STO>P
End

leaves 1584 in P.

(2)

Find the common log of the answer:

>> 2022*log(2022)/log(10)
ans =
          6684.28948783757
          
Then find the antilog of the mantissa:

>> 10^0.28948783757
ans =
          1.94754650808029
          
First four digits are 1947. In fact the accuacy should be reliable up to four fewer (for the four we lose to the characteristic) than show: 1.9475465080, although rounding would bring the last digit to 1; I'd say it does actually truncate to 0.  

However MATLAB can give us all 6685 digits:

sym(2022)^2022

gives an answer that begins

ans =
19475465080987987461884359219297025987247775482742134438609736103478324990332...

and ends

 ...2576971189936148072764791763047709211277938901049215288399825028158870438563056451584,
 
 with thousands of intervening digits.  As the logarithm above shows, there are 6685 digits altogether.


  Posted by Charlie on 2022-03-02 13:54:28
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 (9)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information