Question

Which relation is a function?








A.
{(1, 2); (2, 3); (3, 4); (2, 5)}







B.
{(1, 2); (2, 3); (3, 4); (1, 5)}







C.
{(1, 2); (2, 5); (3, 2); (4, 5)}







D.
{(1, 2); (1, 3); (3, 2); (4, 2)}

Answer 1

the one where there is no repeat in the first coordinates
for example \( {(\color{red}1, 2); (\color{red}1, 3); (3, 2); (4, 2)} \) is not one, because of the repeated \(1\)s

Answer 2

{(1, 2); (2, 5); (3, 2); (4, 5)} ?

Answer 3

correct

Answer 4

\(a=b\implies f(a)=f(b)\)

Answer 5

this property is called "well defined"

Answer 6

as always, the answer is \(C\)

Answer 7

lol