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

Home > Just Math
Descartes roots (Posted on 2019-03-17) Difficulty: 3 of 5
Find the sum of all real numbers x such that
x = (3 - (29x - 1)1/2013) / 29

No Solution Yet Submitted by Danish Ahmed Khan    
No Rating

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution Solution Comment 1 of 1
I started by rearranging the equation into (29x-3)^2013 + 29x - 1 = 0.  

Then I substituted y=29x-3 to get f(y)=y^2013+y+2=0.  There is one obvious real solution y=-1.

The first derivative f'(y)=2013*y^2012+1 is always greater than zero which means f(y) is continuously increasing and then must have only the one real root y=-1.

Then y=-1 implies x=2/29.

  Posted by Brian Smith on 2019-03-17 13:14:25
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (17)
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