10. Suppose x, y, ze Z and x #0. If xyz, then xty and xtz. 11. Suppose x,y e Z. If x²(y + 3) is even, then x is even or y is odd. 12. Suppose a e Z. If a² is not divisible by 4, then a is odd. 13. Suppose xe R. If x5 +7x³ +5x2x4+x² +8, then x ≥ 0.

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
Please a detailed prove would be appreciated for number 10, 12 13
**Exercises for Chapter 5**

**A. Prove the following statements with contrapositive proof.** (In each case, think about how a direct proof would work. In most cases contrapositive is easier.)

1. Suppose \( n \in \mathbb{Z} \). If \( n^2 \) is even, then \( n \) is even.
2. Suppose \( n \in \mathbb{Z} \). If \( n^2 \) is odd, then \( n \) is odd.
3. Suppose \( a, b \in \mathbb{Z} \). If \( a^2(b^2 - 2b) \) is odd, then \( a \) and \( b \) are odd.
4. Suppose \( a, b, c \in \mathbb{Z} \). If \( a \) does not divide \( bc \), then \( a \) does not divide \( b \).
5. Suppose \( x \in \mathbb{R} \). If \( x^2 + 5x < 0 \) then \( x < 0 \).
6. Suppose \( x \in \mathbb{R} \). If \( x^3 - x > 0 \) then \( x > -1 \).
7. Suppose \( a, b \in \mathbb{Z} \). If both \( ab \) and \( a + b \) are even, then both \( a \) and \( b \) are even.
8. Suppose \( x \in \mathbb{R} \). If \( x^5 - 4x^4 + 3x^3 - x^2 + 3x - 4 \geq 0 \), then \( x \geq 0 \).
9. Suppose \( n \in \mathbb{Z} \). If \( 3 \mid n^2 \), then \( 3 \mid n \).
10. Suppose \( x, y, z \in \mathbb{Z} \) and \( x \neq 0 \). If \( x \nmid yz \), then \( x \nmid y \) and \( x \nmid z \).
11. Suppose \( x, y \in \mathbb{Z} \). If \( x^2(y + 3) \)
Transcribed Image Text:**Exercises for Chapter 5** **A. Prove the following statements with contrapositive proof.** (In each case, think about how a direct proof would work. In most cases contrapositive is easier.) 1. Suppose \( n \in \mathbb{Z} \). If \( n^2 \) is even, then \( n \) is even. 2. Suppose \( n \in \mathbb{Z} \). If \( n^2 \) is odd, then \( n \) is odd. 3. Suppose \( a, b \in \mathbb{Z} \). If \( a^2(b^2 - 2b) \) is odd, then \( a \) and \( b \) are odd. 4. Suppose \( a, b, c \in \mathbb{Z} \). If \( a \) does not divide \( bc \), then \( a \) does not divide \( b \). 5. Suppose \( x \in \mathbb{R} \). If \( x^2 + 5x < 0 \) then \( x < 0 \). 6. Suppose \( x \in \mathbb{R} \). If \( x^3 - x > 0 \) then \( x > -1 \). 7. Suppose \( a, b \in \mathbb{Z} \). If both \( ab \) and \( a + b \) are even, then both \( a \) and \( b \) are even. 8. Suppose \( x \in \mathbb{R} \). If \( x^5 - 4x^4 + 3x^3 - x^2 + 3x - 4 \geq 0 \), then \( x \geq 0 \). 9. Suppose \( n \in \mathbb{Z} \). If \( 3 \mid n^2 \), then \( 3 \mid n \). 10. Suppose \( x, y, z \in \mathbb{Z} \) and \( x \neq 0 \). If \( x \nmid yz \), then \( x \nmid y \) and \( x \nmid z \). 11. Suppose \( x, y \in \mathbb{Z} \). If \( x^2(y + 3) \)
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 3 images

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,