Question

This question refers to unions and intersections of relations. Since relations are subsets of Cartesian products, their unions and intersections can be calculated as for any subsets. Given two relations R and S from a set A to a set B, R ∪ S = {(x, y) ∈ A ✕ B | (x, y) ∈ R or (x, y) ∈ S} R ∩ S = {(x, y) ∈ A ✕ B | (x, y) ∈ R and (x, y) ∈ S}. Let A = {−4, 4, 7, 9} and B = {4, 7}, and define relations R and S from A to B as follows. For every (x, y) ∈ A ✕ B, x R y ⇔ |x| = |y| and x S y ⇔ x − y is even. Which ordered pairs are in A ✕ B, R, S, R ∪ S, and R ∩ S? (Use set-roster notation to enter your answers.) A ✕ B = R = S = R ∪ S = R ∩ S =

Answer 1

Answer:

AXB= = {(x, y) ∈ A ✕ B| x ∈ A , y ∈  B}

R= {(x, y) ∈ A ✕ B| x R y ⇔ |x| = |y|}

S={(x, y) ∈ x A ✕ B | S y ⇔ x − y is even}

R ∪ S= {(x, y) ∈ A ✕ B | (x, y) ∈ R or (x, y) ∈ S}

R ∩ S = {(x, y) ∈ A ✕ B | (x, y) ∈ R and (x, y) ∈ S}

Step-by-step explanation:

Let A = {−4, 4, 7, 9} and B = {4, 7},

Then A X B= { (-4,4),(-4,7),(4,4),(4,7),(7,4),(7,7),(9,4),(9,7)}

AXB contains all elements of A and B such that x from A and y is from B.

AXB= = {(x, y) ∈ A ✕ B| x ∈ A , y ∈  B}

R= {(-4,4),(4,4),(7,7)}

R consists all ordered pairs where  |x| = |y|

R= {(x, y) ∈ A ✕ B| x R y ⇔ |x| = |y|}

S= { (-4,4),(4,4),(7,7)}

S={(x, y) ∈ x A ✕ B | S y ⇔ x − y is even}

S consists all ordered pairs where x-y is even.

R ∪ S, = { (-4,4),(4,4),(7,7)}

R US is a set containing subsets of both sets R and S

R ∪ S= {(x, y) ∈ A ✕ B | (x, y) ∈ R or (x, y) ∈ S}

R ∩ S=  {(-4,4),(4,4),(7,7)}

R ∩ Sis a set containing subsets only which are common between sets R and S

R ∩ S = {(x, y) ∈ A ✕ B | (x, y) ∈ R and (x, y) ∈ S}