em: For every integer k, if k > 0 then k² + 2k + 1 is composite. Suppose k is any integer such that k > 0. If k² + 2k + 1 is composite, then k2 + 2k + 1 1

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

Can someone explain this particular HW question to me?

Theorem: For every integer k, if k > 0 then k² + 2k + 1 is composite.
"Proof: Suppose k is any integer such that k > 0. If k² + 2k + 1 is composite, then k² + 2k + 1 = rs for some integers r and s such that
1<r < k² + 2k +1
and
1< s < k² + 2k + 1.
Since
k² + 2k +1 = rs
and both r and s are strictly between 1 and k² + 2k + 1, then k² + 2k + 1 is not prime. Hence k2 + 2k + 1 is composite as was to be shown."
In the above:
it is correct because of boundedness
O it is incorrect because it assumes what is to be proved
it is incorrect because the definitions are incorrect
it is correct because of deMorgan's law
Transcribed Image Text:Theorem: For every integer k, if k > 0 then k² + 2k + 1 is composite. "Proof: Suppose k is any integer such that k > 0. If k² + 2k + 1 is composite, then k² + 2k + 1 = rs for some integers r and s such that 1<r < k² + 2k +1 and 1< s < k² + 2k + 1. Since k² + 2k +1 = rs and both r and s are strictly between 1 and k² + 2k + 1, then k² + 2k + 1 is not prime. Hence k2 + 2k + 1 is composite as was to be shown." In the above: it is correct because of boundedness O it is incorrect because it assumes what is to be proved it is incorrect because the definitions are incorrect it is correct because of deMorgan's law
Expert Solution
trending now

Trending now

This is a popular 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,