❀ Here, We are given relation from A to B [ Suppose ] & We have to identify whether they are function or not from the relation A to B.
- { ( 1 , 1 ) , (2 , 2 ) , ( 3 , 3 ) , (4 , 4 ) , ( 5 , 5 )}
⇢ This is a function from A to B because every element of Set A has unique image in set B.
- {( 0,0 ) , ( 1 , 1 ) , ( 1 , -1 ) , ( 4 , 2 ) , ( 4 , -2 ) }
⇢ This is not a function because two of the elements of Set A ( 1 & 4 ) are associated to elements -1 , 1 & 2 , -2 respectively of Set B
- { ( 2 , 1 ) , (2 , 2 ) , (2 , 3 ) , (2 , 4 ) , (2 , 5 )
⇢ This is not a function because the element of Set A ( 2 ) is associated to all the elements of Set B.
- { ( 1 , 5 ) , ( 2 , 4 ) , ( 3 , 3 ) , (2 , 2 ) , ( 1 , 1 )
⇢ This is not a function because the elements of Set A ( 1 & 2 ) are associated to elements ( 5 , 1 & 4 , 2 ) of Set B respectively.
♨ Q. What is function ? How can we identify whether the given relation is a function ?
⟶Function is a special type of relation. Function is the refinement of relation. In a relation from A to B , every element of Set A has only one ( distinct ) image in B. In other words , if no two different ordered pairs have the same first component , then it is a function.
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