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

Home > Just Math
Evaluate this sum (Posted on 2005-12-21) Difficulty: 4 of 5
Evaluate this sum in terms of n (the number of terms):
        1      2       4        8          16         
   S = --- + ----- + ----- + ------- + ---------- + ..... 
        2      5       41     3,281    21,523,361              

See The Solution Submitted by pcbouhid    
Rating: 4.3333 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: Using Charlie's idea (spoiler?) | Comment 4 of 14 |
(In reply to Using Charlie's idea (spoiler?) by Bob Smith)

The formula you give checks out if you change the power of 2 in the numerator to n+2 rather than n+1, if you're starting numbering with n=0.  If starting numbering with n=1, then it's the power of 2 in the denominator that should change, from n+1 to just n.  In any case, the power of 2 in the numerator should be one higher than the power of 2 in the denominator in order to get the sequence 1/2, 1/10, 1/410, 1/1345210, 1/28953440450810.
  Posted by Charlie on 2005-12-21 15:54:00

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 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information