Algebra> MATHS...

LET SET A (1,2,3,4,5) & B(1,2,3) THEN

a) NUMBER OF ONTO FUNCTIONS FROM A TO B ?

b) NUMBER OF ONE ONE FUNCTIONS FROM A TO A SUCH THAT F(i) ≠ i, i € A

c) NUMBER OF INTO FUNCTIONS FROM A TO B ?

PLZ REPLY

rohit kumar , 14 Years ago

Grade 12

1 Answers

SAGAR SINGH - IIT DELHI

Last Activity: 14 Years ago

Dear student,

I will give u very short trick:

In general no of onto functions from A to B containing m and n elements respectively is

$\sum _{r=1}^{n} (-1)^{n-r} nC_r.r^m$

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