Question

If A = {1, 2, 3} and B = {a, b, c, d}, then × is equal to _______.​

Answer 1

Answer:

Well, it is a simple question, as you will see.

Given: A=(1,2,3), B=(a,b,c)

Number of elements, n(A)=3, & n(B)=3.

Then number of relations from A to B =n(A)*n(B)

Answer=3*3=9

As you can also crosscheck by forming pairs, AxB ={(1,a),(1,b),(1,c),(2,a),(2,b),(2,c),(3,a),(3,b),(3,c)}

If you are facing a problem in forming relations, then the picture below you can see, the elements are written as written then draw strainght lines through them, for vertical elements draw horizontal lines, and for horizontal elements draw vertical lines.

The point of intersections represent the order pair between the elements from which the lines have come up.

Answer 2

n (A) = 3

n (B) = 3

No. of relations= 2* n (A) × n (B)

=2*3×3

=2*9

=512