Solution:
A function is always a relation but a relation is not always a fucntion.
For example
we can make a realtion of student roll number and their marks obtained in mathematics.
So we can have pairs like (a,b), (c,d)..etc.
Its a realtion but it may not be function. Because function follows that for same input there should not be diffrent output. But this doesn't holds a necessary condition in case of relation.
Because two diffrent students with two diffrent Roll number may have same marks.
Answer: Every domain element is paired with only one range element. No two pairs share the same domain element.
Step-by-step explanation:
