Recent content by fleuryf

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    Prove or disprove that subsets a and b of x and f:x->y f(f-1(a))=a

    Yes, turns out there was a typo in the problem as it was given which explains the difficulty in solving it. A is indeed a subset of Y which makes the statement f(f^-1(A)) true if the mapping is surjective but in the example X={1,3,5} Y={2,4,6,8} f:X->Y = {(1,2),(3,4),(5,6)} Where f is...
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    Prove or disprove that subsets a and b of x and f:x->y f(f-1(a))=a

    Homework Statement Prove or disprove that for any non empty sets X and Y, any subset A of X, and f:X->Y, f(f^-1(A))=A Homework Equations The Attempt at a Solution I know that for x element of A f(x) = f(A) so x is an element of f^-1(f(A)). If I can assume f is injective then I can go from...
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    Limit problem with b^m*e^-(sb)

    Homework Statement show for m element of Natural numbers lim b->oo b^m/(e^(sb)) = 0 Homework Equations The Attempt at a Solution Here is what I've started with so far but have ended up at a dead end. I just would like some help to point me in the right direction if possible...