Anonymous asked in Science & MathematicsMathematics · 1 month ago

Suppose you have two sets A and B such that |A|=4 and |B|=10. Find the number of one-to-one functions f: A⟶B Number of functions = [a]. ?

I wrote 10^4 as my answer but the correct answer is 10!/6!. I don't understand where you get the 6 from. It's probably from 10-4 but I don't understand why you need to do that. Can someone please explain this question?

1 Answer

  • ted s
    Lv 7
    1 month ago

    take a 1st element from can be associated with 10 different elements from B ; the 2nd from A can be associated with only 9 from B , 3rd ---> 8 and 4th ---> 7.....10 x 9 x 8 x 7 ≡ 10! / 6!

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