Question

Let A = [1, 2] and B = [3, 4]. Find the total number of relation from A into B.

Answer 1

We have:
A = {1, 2} and B = {3, 4}
Now,
$n(A\times B)=n\left(A\right)\times n\left(B\right)=2\times 2=4$
There are 2ⁿ relations from A to B, where n is the number of elements in their Cartesian product.
∴ Number of relations from A to B is 2⁴ = 16.