Q9 of 65 Page 73

Let R be a relation on Z, defined by (x, y) ϵ R ↔ x2 + y2 = 9. Then, write R as a set of ordered pairs. What is its domain?

x2 + y2 = 9


We can have only integral values of x and y.


Put x = 0 , y = 3 , 02 + 32 = 9


Put x = 3 , y = 0 , 32 + 02 = 9


R = {(0, 3) , (3, 0) , (0 , -3) , (-3 , 0)}


The domain of R is the set of first co-ordinates of R


Dom(R) = {-3 , 0 , 3}


The range of R is the set of second co-ordinates of R


Range(R) = {-3 , 0 , 3}


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