Question

Select the correct answer.

Which relation is a function?

A. {(2,3), (1,5), (2,7)}

B. {(-1,5), (-2,6), (-3,7)}

C. {(11,9), (11,5), (9,3)}

D. {(3,8), (0,8), (3,-2)}

Answer 1

The answer is option B.

Explanation:

A rule that uniquely associates elements of one set A with the elements of another set B and each element in set A maps to only one element in set B.

Each element from X is related to only one element in Y. But it is okay for two different elements in X to be related to the same element in Y. So its still a function. Let suppose

{ (1,a) , (2, b) , (2, c) , (3, d) }

This relation is not a function from X to Y because the element 2 in X is related to two different elements, b and c.