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Question
Is the given relation a function? Give reasons for your answer.
f = {(x, x) | x is a real number}
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Solution
f = {(x, x) | x is a real number}
This means the relation f has elements which are real number.
Therefore, for every x ∈ R there will be unique image.
A relation is said to be function if every element of one set has one and only one image in other set.
Hence, f is a function.
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