sir, if for a function f(x), and for another function g(y) , if I prove that gof(x) = x & fog(y)=y, should I have to prove that f is an onto function? Or if a question asks me to prove that f is an onto function , can I apply the above mentioned method? Please explain it.

Asked by shivendra upadhyay | 13th Mar, 2013, 11:40: AM

Expert Answer:

If the question asks you to prove f is onto, then the proper procedure is to prove that for each b in set B, there exists atleast one a in A such that f(a) = b. Note that here, f is a function from A to B.

Answered by  | 15th Mar, 2013, 11:23: AM

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