Question

Q18. Which of the following relations is
not a function?
R= {(1,2), (3,4),(2,1),(5,1)}
R= {(2,1),(4,4)(3,1),(5,1)}
R= {(1,2), (3,4)(2,1),(5,2)}
R={(1,2), (1,4)(3,1),(5,1)}​

Answer 1

Answer:

The last option is not a function, but just a relation.

Step-by-step explanation:

The last option is not a function as the element 1 of the domain has two images, that is, 2 and 4, in the range (subset of the co-domain) of the function, which violates the condition for a relation to be a function, which is that a relation is called a function, if and only if, the elements in the range have a unique pre-image existing in the domain of the function.

Hope this helps.