Online Course Discussion Forum

MC4 Problem 2 Clarification

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MC4 Problem 2 Clarification
by Derek Dong - Tuesday, December 25, 2018, 8:27 AM

In the Counting 2 handout's problem section number 2, it says n/2<=k<=n. Is this k fixed for the function f(X) or does the second condition mean n/2<=f(x)<=n for all x in X? (also, why are there absolute bars? if f:X->X and all elements of X are positive, why are absolute values necessary? Unless it actually means the size of the range of f(x) is equal to k?)

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Re: MC4 Problem 2 Clarification
by Areteem Professor - Wednesday, December 26, 2018, 4:47 PM

$k$ is a fixed number;

$|f(x)|=k$ is a mistake.  It should be $f(X)|=k$, meaning the range of $f$ has size $k$.  I will fix this together with the other one.