Class 11 Maths Relation Functions | Functions In terms of Relation |

**Functions: In terms of Relation**

A relation is said to be a function if every element of set A has only 1 image/output in set B. Note that other way round need not be true, more than 1 elements of Set A can have same image/output in set B. E.g. two elements of Set A 5 & -5 correspond to element 25 of Set B, still it is a function.

Relation between set A & B where 1^{st} letter of element in B is element in A , is not a function as element b in Set A has two different image/output in Set B.

We can say that Function is a subset of Relation.

**Numerical**: Whether given relation is a function or not? R = {(1,2),(2,3),(3,4), (4,5), (5,6), (6,7)}

**Solution**: Let’s draw arrow diagram. We can see that for every element of set A , it has only 1 image/output in set B. Thus it is a function.

**Real & Real Valued functions**

Real Value function: Range à R or subset of R (that is output is R but not input)

Real function: Both range & domain à R or subset of R

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