Adding Rational and Irrational NumbersDate: 11/09/1999 at 11:14:45 From: Jessica Troise Subject: Abstract Math I I was wondering how you could prove that a rational number added to an irrational number results in an irrational number. Date: 11/09/1999 at 12:54:15 From: Doctor Wilkinson Subject: Re: Abstract Math I When you want to prove something is irrational you should almost always use an indirect proof. So suppose that x is rational and y is irrational. You want to show that x + y is irrational, so you assume it's rational. So you have x rational y irrational x + y = z rational What happens if you solve x + y = z for y in terms of x and z? - Doctor Wilkinson, The Math Forum http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994-2015 The Math Forum
http://mathforum.org/dr.math/