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If X and Y are two non-empty sets, where f:XtoY is function defined such that f(C)={f(x):x inC}andf'(D)={x:f(x)inD} for DsubeYfor any AsubeXandBsubeY, then : |
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Answer» `f(f^(-1)(B))=B` only if `B=f(X)` |
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