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A has 3 elements and B has 6 elements. How many functions are there from A to B? …

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$A$ has $3$ elements and $B$ has $6$ elements. How many functions are there from $A$ to $B$ ? How many of them are one-one? How many relations are there from $A$ to $B$ ?

Need a reminder? The key ideaShow

From $m$ elements to $n$ elements there are $n^m$ functions, $n(n - 1)\cdots(n - m + 1)$ one-one functions and $2^{mn}$ relations.

The worked solution

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A has 3 elements and B has 6 elements. How many functions are there from A to B? …

The worked solution

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