Turn on thread page Beta
    • Thread Starter
    Offline

    2
    ReputationRep:
    Is this a proof by contradiction (we suppose that root 2 can be expressed as the ratio of two coprime integers and then find that they're not actually coprime) or a proof by infinite descent (the fraction can be simplified forever so it can't be rational)? Is there any way to prove it without supposing at first that it is rational?
    Offline

    14
    The contradiction is shown by infinite descent. There are other methods, such as: http://en.wikipedia.org/wiki/Square_...#Another_proof and the method below that.

    P.S. "infinite descent" is a cool sounding phrase. There should be a film or band with that title.
    Offline

    0
    ReputationRep:
    yeah its a proof by contradiction!
    Offline

    15
    ReputationRep:
    Actually, its proof by cases. According to a book I have called how to prove it.
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 10, 2008

2,723

students online now

800,000+

Exam discussions

Find your exam discussion here

Poll
Should predicted grades be removed from the uni application process
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.