CTK Exchange
Front Page
Movie shortcuts
Personal info
Awards
Reciprocal links
Terms of use
Privacy Policy

Interactive Activities

Cut The Knot!
MSET99 Talk
Games & Puzzles
Arithmetic/Algebra
Geometry
Probability
Eye Opener
Analog Gadgets
Inventor's Paradox
Did you know?...
Proofs
Math as Language
Things Impossible
My Logo
Math Poll
Other Math sit's
Guest book
News sit's

Recommend this site

Manifesto: what CTK is about Search CTK Buying a book is a commitment to learning Table of content Products to download and subscription Things you can find on CTK Chronology of updates Email to Cut The Knot Recommend this page

CTK Exchange

Subject: "Proving an expression irrational"     Previous Topic | Next Topic
Printer-friendly copy     Email this topic to a friend    
Conferences The CTK Exchange This and that Topic #762
Reading Topic #762
Neil_Parker
Member since Apr-13-07
May-01-07, 06:34 AM (EST)
Click to EMail Neil_Parker Click to send private message to Neil_Parker Click to view user profileClick to add this user to your buddy list  
"Proving an expression irrational"
 
   In the section on irrationality of sqrt 2 it is shown that sqrt(n^2+1) and sqrt(n^2-1) are irrational with n any integer greater than 1. I think the arguement applies equally to any rational greater than 1. Does it follow that the ratio sqrt(n^2-1)/sqrt(n^2+1) is also irrational ? Also does the proof hold for roots other than square eg cube roots, fourth roots etc ?

Neil

Neil


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top
alexbadmin
Charter Member
1995 posts
May-01-07, 04:47 PM (EST)
Click to EMail alexb Click to send private message to alexb Click to view user profileClick to add this user to your buddy list  
1. "RE: Proving an expression irrational"
In response to message #0
 
   sqrt(n^2+1) is rational for n = 3/4 and
sqrt(n^2-1) is rational for n = 5/4


  Alert | IP Printer-friendly page | Reply | Reply With Quote | Top

Conferences | Forums | Topics | Previous Topic | Next Topic

You may be curious to have a look at the old CTK Exchange archive.
Please do not post there.

Copyright © 1996-2018 Alexander Bogomolny

Search:
Keywords:

Google
Web CTK