Let A={1,2,3,4,5} and B={6,7,8,9,10,11,12}. How many functions f:A->B are such that f -1({6,7,8})={1,2}?
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Originally Posted by sbankica Let A={1,2,3,4,5} and B={6,7,8,9,10,11,12}. How many functions f:A->B are such that f -1({6,7,8})={1,2}? Any function is such that . There are such functions. WHY? How many functions Can you answer the question posted?
Last edited by Plato; November 9th 2009 at 02:43 PM.
4^3?
so answer is: (3^2)(4^3)
Originally Posted by sbankica so answer is: (3^2)(4^3) You got it!
Originally Posted by Plato Any function is such that . There are such functions. WHY? How many functions Can you answer the question posted? PLATO, you have been so helpful. I see the following six functions: f(1)=6; f(1)=7; f(1)= 8; f(2)=6; f(2)=7; f(2)=8 What are the other three functions? Thank you.
Originally Posted by oldguynewstudent I see the following six functions: f(1)=6; f(1)=7; f(1)= 8; f(2)=6; f(2)=7; f(2)=8 What are the other three functions?
Originally Posted by Plato Thank you so much. I keep forgetting that the definition of a function maps every element in the domain to a unique element in the codomain. This will really help my understanding in the future.
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