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Let A = {1, 2, 3}, B = {4, 5, 6, 7} and let f = {(1, 4), (2, 5), (3, 6)} be a function from A to B. Show that f is one-one.

Class 12, NCERT Chapter 1,  Exercise 1.2, Q6

It is given that A={1,2,3} B={4,5,6,7}

f: A→B defined as f(x)= {(1, 4), (2, 5), (3, 6)} 
Therefore f(1)=4,  f(2)=5,  f(3)=6
It is seen that the images of distinct elements of A under f are distinct. Hence, function f is one-one

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