Math Problem Statement

List the ordered pairs in the relation 𝑅 from 𝐴 = {0,1,2,3,4} to 𝐡 = {0,1,2,3}, where (π‘Ž, 𝑏) ∈ 𝑅 if and only if (a) π‘Ž = 𝑏 (b) π‘Ž + 𝑏 = 4 (c) π‘Ž > 𝑏 (d) π‘Ž|𝑏 (e) gcd(π‘Ž, 𝑏) = 1 (f) lcm(π‘Ž, 𝑏) = 2

Solution

Let's analyze the conditions one by one for the relation RR from set A={0,1,2,3,4}A = \{0,1,2,3,4\} to set B={0,1,2,3}B = \{0,1,2,3\}.

(a) a=ba = b

The ordered pairs where a=ba = b are simply those where the elements of AA and BB are equal: R={(0,0),(1,1),(2,2),(3,3)}R = \{(0,0), (1,1), (2,2), (3,3)\}

(b) a+b=4a + b = 4

The ordered pairs where the sum of aa and bb equals 4: R={(0,4),(1,3),(2,2),(3,1),(4,0)}R = \{(0,4), (1,3), (2,2), (3,1), (4,0)\} However, note that bb must be in B={0,1,2,3}B = \{0,1,2,3\}, so exclude pairs with b=4b = 4. Thus, the relation is: R={(1,3),(2,2),(3,1),(4,0)}R = \{(1,3), (2,2), (3,1), (4,0)\}

(c) a>ba > b

The ordered pairs where aa is greater than bb: R={(1,0),(2,0),(2,1),(3,0),(3,1),(3,2),(4,0),(4,1),(4,2),(4,3)}R = \{(1,0), (2,0), (2,1), (3,0), (3,1), (3,2), (4,0), (4,1), (4,2), (4,3)\}

(d) a∣ba \mid b

The ordered pairs where aa divides bb (meaning bb is a multiple of aa): R={(1,1),(1,2),(1,3),(2,2),(0,0)}R = \{(1,1), (1,2), (1,3), (2,2), (0,0)\} Note that 00 divides 00 but is typically not considered a divisor for non-zero numbers.

(e) gcd⁑(a,b)=1\gcd(a, b) = 1

The ordered pairs where the greatest common divisor (gcd) of aa and bb is 1: R={(1,0),(1,2),(1,3),(2,3),(3,2),(3,4)}R = \{(1,0), (1,2), (1,3), (2,3), (3,2), (3,4)\} For gcd(0,b)gcd(0, b) where b≠0b \neq 0, the gcd is bb, so these are not included.

(f) lcm(a,b)=2\text{lcm}(a, b) = 2

The ordered pairs where the least common multiple (lcm) of aa and bb is 2: R={(1,2),(2,1)}R = \{(1,2), (2,1)\} Here (1,2)(1,2) and (2,1)(2,1) are the only pairs that give an lcm of 2.


Would you like details or have any questions?

Related Questions:

  1. How is the gcd of two numbers calculated?
  2. What is the significance of lcm in number theory?
  3. Can you explain the division algorithm used in condition (d)?
  4. What are some real-world applications of relations in set theory?
  5. How can we generalize these conditions for larger sets?

Tip: When working with relations, ensure you clearly understand the definitions of operations like gcd, lcm, and divisibility, as they often appear in various mathematical contexts.

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Math Problem Analysis

Mathematical Concepts

Set Theory
Relations

Formulas

gcd(a, b)
lcm(a, b)

Theorems

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Suitable Grade Level

High School