contestada

Let A be the set of all lines in the plane. Define a relation R on A as follows. For every l1 and l2 in A, l1 R l2 ⇔ l1 is parallel to l2. (Assume that a line is parallel to itself). Which of the following is true for R?
A. R is reflexive.
B. R is symmetric.
C. R is transitive.
D. R is neither reflexive, symmetric, nor transitive.

Respuesta :

Answer:

Hence, the relation R is a reflexive, symmetric and transitive relation.

Given :

A be the set of all lines in the plane and R is a relation on set A.

[tex]R=\{l_1,l_2\in A|l_1 \;\text{is parallel to}\; l_2\}[/tex]

To find :

Which type of relation R on set A.

Explanation :

A relation R on a set A is called reflexive relation if every [tex]a\in A[/tex] then [tex](a,a)\in R[/tex].

So, the relation R is a reflexive relation because a line always parallels to itself.

A relation R on a set A is called Symmetric relation if [tex](a,b)\in R[/tex] then [tex](b,a)\in R[/tex] for all [tex]a,b\in A[/tex].

So, the relation R is a symmetric relation because if a line [tex]l_1[/tex] is parallel to the line [tex]l_2[/tex] the always the line [tex]l_2[/tex] is parallel to the line [tex]l_1[/tex].

A relation R on a set A is called transitive relation if [tex](a,b)\in R[/tex] and [tex](b,c)\in R[/tex] then [tex](a,c)\in R[/tex] for all [tex]a,b,c\in A[/tex].

So, the relation R is a transitive relation because if a line [tex]l_1[/tex] s parallel to the line [tex]l_2[/tex] and the line [tex]l_2[/tex] is parallel to the line [tex]l_3[/tex] then the always line [tex]l_1[/tex] is parallel to the line [tex]l_3[/tex].

Therefore the relation R is a reflexive, symmetric and transitive relation.

Otras preguntas