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Which of the following correspondences are functions?
THE RULE IS:
If the correspondence has only ONE output for each given input, then it is a function.
If the correspondence has MORE THAN ONE output for some input, then it is NOT a function.
Now let's look how the rule does work.
ID numbers to students - Every ID relates to ONLY ONE student
(assuming that the ID service is organized correctly and properly . . . )
Hence, this correspondence is a function.
Students to ID numbers - Every student may have ONLY ONE ID number.
(assuming that the ID service is organized correctly and properly . . . )
Hence, this correspondence is a function.
Buildings to zip codes - Every building has ONLY ONE zip code. Function.
Zip codes to buildings - Zip code usually (as a rule) has more than one building related to it: NOT a function.
Birthdays to first graders - Many first graders may have the same birthday. Not a function.
First graders to birthdays - Every first grader has only one birthday. Function.
Football players to heights
Heights to football players
Houses to house numbers
House numbers to houses
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Amelia, I made some positions for you to show how it works.
I sincerely hope it will help you to get understanding, and I ask you to make further examples on your own, to check your understanding.
You may then post your results, and we will check them.
H a p p y l e a r n i n g ! !
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Comment from student:
Football players to heights would be a function, because each football player has only one height
Heights to football players is not a function because different players can have the same height
Houses to house numbers is a function because a house can only have one number
House numbers to houses in not a function because different houses in different places can have the same number.
I hope this is right! The question definitely makes more sense now. Amelia Brown
My response: Amelia, all your answers are perfectly correct.
My congratulations ! Brilliant work ! !
I am very glad for you.