Medal plus Fan!!

Determine which relation is a function.

http://prntscr.com/9f197y

Question

Medal plus Fan!!

Determine which relation is a function.

http://prntscr.com/9f197y <--- A & B

http://prntscr.com/9f1a7h <--- C & D

theedwardsfamily · Answer

Is it B?

owlcoffee · Answer

When we have two variables x and y, and we name them in such a way that one can have any arbitrary value while the other is solvable for, we call this relationship "functional relation between variables".
This of course is notated as
$$y=\phi (x)$$
Meaning, "y" is a variable that depends on "x" and you know it better as f(x).
Now, $\phi (x)$ is often represented by a mathematical expression which determines the pattern of the functionality of the variable "y".

theedwardsfamily · Answer

so b? @Owlcoffee

owlcoffee · Answer

Maybe... Why do you think it's "B"?

theedwardsfamily · Answer

because, it passes through the line(the function). http://prntscr.com/9f1hym

theedwardsfamily · Answer

@Owlcoffee

owlcoffee · Answer

Wat do you mean it "passes through the line".?
The circle cuts the x-axis as well, but it is not a function.
There is something very important, traditional functions whose variable depends on the other have that is important.

theedwardsfamily · Answer

Im so confused. >.> sorry

owlcoffee · Answer

B is correct. 
not because it intersects the axis, but because every x in the domain has one and only one value of "y", that is a definition for "function".