Question

Can anyone tell me how to know if the relation is a function? I'm trying to teach my daughter how to do this before she goes back to school, but I can't remember

Answer 1

What

Answer 2

If there is one y for every x (in a two variable problem) then it's a function

Answer 3

So once you figure out your domain and ranges then you will know if it is a function?

Answer 4

If there exists an x such that it has only one y value, then it is a function

Answer 5

So if there is an x such that it has two y values, it is not a function

Answer 6

Oh boy it has been a long time lol

Answer 7

Does she have to figure out the range and domains first?

Answer 8

Look at your first problem. It's not a function, do you know why?

Answer 9

No because everything has an x and y lol

Answer 10

No no look at each ordered pair. The first says x=3 leads to y=4. But then another pair says x=3 leads to y=2

Answer 11

After what I told you about what makes something a function, that can't work. A single x cannot have more than one y value

Answer 12

Now using that knowledge, tell me if the next one is a function

Answer 13

oooooo cause it maps to 2&4

Answer 14

Yes, and the independent variable is only allowed one dependent variable

Answer 15

One dependent value I should say

Answer 16

Thank you!! One more question When you do domain and ranges you don't double the numbers right? so if y has 2 twice then she only writes it once?

Answer 17

Oh yeah you only write it once

Answer 18

and does she write down the 0 on domain and ranges? or not write 0

Answer 19

She writes the 0. It's still a number

Answer 20

There are some functions that never reach 0. Take x^2 + 1 for example. It never reaches 0

Answer 21

Ok I thought so. Thank you for the help I may be back on here again lol. 8th grade was a LONG time ago

Answer 22

8th grade was 9 years ago for me. My gosh I guess I'm old too