SOLUTION: is (date of birth, person) a function? is (thumbprint, person) a function? is (area code, state) a function? is (amount of sales tax, purchase total) a function? is (sales tax

Question 644715: is (date of birth, person) a function?
is (thumbprint, person) a function?
is (area code, state) a function?
is (amount of sales tax, purchase total) a function?
is (sales tax percentage, purchase total) a function?
is (jersey number, NFL football player) a function?
is (jersey number, current Dallas Cowboys player) a function?
is (person, date of birth) a function?
is (person, thumbprint) a function?
is (state, area code) a function?
is (purchase total, amount of sales tax) a function?
is (purchase total, sales tax percentage) a function?
is (NFL football player, jersey number) a function?
is (current Dallas Cowboys player, Jersey number) a function?
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
is (date of birth, person) a function? No, one date corresponds to many people being born on that day (people share the same birth date). Each input (date of birth) maps to MORE THAN ONE output (person), so it fails to be a function.

Note: if it were the other way around, then it would be a function since a person has only one date of birth.

is (thumbprint, person) a function? Yes, thumbprints are unique to every individual. Each input (thumbprint) maps to ONLY ONE output (person)

is (area code, state) a function? Yes, each area code is unique to each region of the country. Each input (area code) maps to ONLY ONE output (state)

I'll let you do the rest. The basic idea is that if x maps to more than one y value, then it's NOT a function. If you can show that each x maps to only one y value, then it would be a function.
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