Theorem: There is no rational number x such that 1 < x < 2. Proof: We use proof by contradiction. So suppose there are rational numbers between 1 and 2, and let x be the smallest one. Because x is rational, we can write x = where a and b are integers. Now let y = *1. Then y = , so y is rational. a+b %3D The assumption that x > 1 gives x +1 > 2, which implies that y > 1. The assumption that x > 1 also gives 2x > x +1, which implies that y < x. But now y is a rational number between 1 and 2 which is smaller than x. This contradicts the assumption that x was the smallest one. So the theorem is true using proof by contradiction. D.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
lere's an incorrect theorem with an incorrect proof.
Theorem: There is no rational number x such that 1 < x < 2.
Proof: We use proof by contradiction. So suppose there are rational numbers between 1 and 2, and let x be the smallest one. Because x is
rational, we can write x = where a and b are integers. Now let y = 1. Then y = ", so y is rational.
%3D
a+b
%3D
The assumption that x > 1 gives x +1 > 2, which implies that y > 1. The assumption that x > 1 also gives 2x > x +1, which implies that
y < x.
But now y is a rational number between 1 and 2 which is smaller than x. This contradicts the assumption that x was the smallest one. So the
theorem is true using proof by contradiction. D.
Transcribed Image Text:lere's an incorrect theorem with an incorrect proof. Theorem: There is no rational number x such that 1 < x < 2. Proof: We use proof by contradiction. So suppose there are rational numbers between 1 and 2, and let x be the smallest one. Because x is rational, we can write x = where a and b are integers. Now let y = 1. Then y = ", so y is rational. %3D a+b %3D The assumption that x > 1 gives x +1 > 2, which implies that y > 1. The assumption that x > 1 also gives 2x > x +1, which implies that y < x. But now y is a rational number between 1 and 2 which is smaller than x. This contradicts the assumption that x was the smallest one. So the theorem is true using proof by contradiction. D.
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,