which of the following sets of ordered pairs are functions? Which of them are only relations?

1. {(0,0), (1,-1), (-3,2), (2,-2), (-5,5),(7,-7)
2. {(x,y): x is a positive integer, y is a factor of x}
3. {(1,2), (-2,-4), (3,6), (4,8), (-7.-14), (0,0)}
4. {(4,2), (4,-2), (1,1), (1,-1), (9,3), (9,-3), (25,5), (25,-5)

Question

which of the following sets of ordered pairs are functions? Which of them are only relations?

1. {(0,0), (1,-1), (-3,2), (2,-2), (-5,5),(7,-7)
2. {(x,y): x is a positive integer, y is a factor of x}
3. {(1,2), (-2,-4), (3,6), (4,8), (-7.-14), (0,0)}
4. {(4,2), (4,-2), (1,1), (1,-1), (9,3), (9,-3), (25,5), (25,-5)

chaise · Answer

A function is a relation between a set of inputs and a set of potential outputs with the property that each input is related to exactly one output. 

Does this help at all?

chaise · Answer

where x is the input, and y is the output.

anonymous · Answer

which of them are sets of ordered pairs? and which of tem are only relations?

nikolas · Answer

Unless I'm mistaken, they are all sets of ordered pairs - an ordered pair is any pair of objects like (a,b). A function is a kind of relation. Try the "vertical line test" - if you graph the numbers and you can draw a vertical line through more than one point on the graph, it isn't a function. As chaise explained, an input of a function ("x" for example) is related to only ONE output ("y"). Any one of those sets of ordered pairs that is not a function is just a relation.

nikolas · Answer

This article may help: http://www.purplemath.com/modules/fcns.htm

anonymous · Answer

thanks ;8