Question

The total number of injective mappings from a set with m elements of distinct functions from A to A is

Solution

Correct option is

 can have n images in B, but the elements awill have only (n – 1) images as the mappings are to be one-one (injective).

Similarly the elements awill have (n – 2) images. Hence the total number of mappings will be

              = n(n – 1) (n – 2)…

              = n (n – 1) (n – 2) …(n – m – 1)

Multiply above and below by

(n – m) (n – m – 1)…3. 2. 1

SIMILAR QUESTIONS

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Q5

 

 

Q6

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Q7

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Q8

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Q9

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Q10

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