(i)
The sets A, B, C and D are given { 1,2 }, { 1,2,3,4 }, { 5,6 } and { 5,6,7,8 }respectively.
The Cartesian product of sets A and ( B∩C ) is,
B∩C={ 1,2,3,4 }∩{ 5,6 } =ϕ
Here, ϕ is a null vector.
Then,
A×( B∩C )={ 1,2 }×ϕ =ϕ (1)
The Cartesian product of A×B is,
A×B={ ( 1,1 ),( 1,2 ),( 1,3 ),( 1,4 ),( 2,1 ),( 2,2 ),( 2,3 ),( 2,4 ) }
The Cartesian product of A×C is,
A×C={ ( 1,5 ),( 1,6 ),( 2,5 ),( 2,6 ) }
Then, the value of ( A×B )∩( A×C ) is,
( A×B )∩( A×C )=ϕ(2)
Hence, equations (1) and (2) are the same, so the system is verified.
(ii)
The value of Cartesian product of A×C is,
A×C={ ( 1,5 ),( 1,6 ),( 2,5 ),( 2,6 ) }(3)
The value of Cartesian product of B×D is,
B×D={ ( 1,5 ),( 1,6 ),( 1,7 ),( 1,8 ),( 2,5 ),( 2,6 ),( 2,7 ),( 2,8 ), ( 3,5 ),( 3,6 ),( 3,7 ),( 3,8 ),( 4,5 ),( 4,6 ),( 4,7 ),( 4,8 ) } (4)
All the elements in the set A×C are the elements of B×D.
Hence, A×C is a subset of B×D.