which is a function?

Question

anonymous · Answer

$$A. \left[ y \right]$$

parthkohli · Answer

The guy which has a unique mapping to it.

anonymous · Answer

do you have a better example?

dean.shyy · Answer

This may help: http://is.gd/PItqZG

anonymous · Answer

That does help Dean,shy

anonymous · Answer

$$A. x=\left[ y \right]$$
$$B. y= \left| x \right|$$
$$C. x ^{2} + y ^{2} = 49$$
$$D. x = y ^{2}$$

nincompoop · Answer

what would be your answer ?

anonymous · Answer

which ever one is a function. . .

nincompoop · Answer

which do you think IS a function in the choices you've been provided?

anonymous · Answer

D?

nincompoop · Answer

why?

anonymous · Answer

because it has a y. lol im so sorry. im tired!!

nincompoop · Answer

hehehe I don't think you read the attachment that was shared to you.  read it a little bit, will you? it will help you answer a lot of problems regarding functions

anonymous · Answer

C?

nincompoop · Answer

okay, you're just obviously guessing.  did you read the attachment?

anonymous · Answer

i did. but none of them look like that. or else i would have known it at first.

nincompoop · Answer

so what do you understand about function?

nincompoop · Answer

by the way, do you understand the [ ] and | | in A and B respectively?

anonymous · Answer

i understand the absolute value signs but i dont know what the bracket  things are

nincompoop · Answer

brackets and curly braces are used when there are nested parentheses to avoid confusion 
–{2x – [3 – (4 – 3x)] + 6x}

anonymous · Answer

so it would be B because the graph of y = |x| passes the vertical line test??

nincompoop · Answer

so your A is just simply x = y, which is y = x 
now if you read the attachment, this could mean
f(x) = x

anonymous · Answer

ok so it could mean f(x) = x?

nincompoop · Answer

yes, it means that the output is the same as the input
f(x) the x inside the parenthesis, gives an output of x
f(x) = x
f(2) = 2
f(blah) = blah

anonymous · Answer

oh ok. that makes  sense now!

anonymous · Answer

thanks! i apologize! Im soo tired!

nincompoop · Answer

will it pass the vertical or horizontal line test?

anonymous · Answer

if x = 2 or 3 or 4 etc. it will pass the vertical line test which means it is a function. But it will not pass the horizontal line test which means it is not a 1 - 1 function.

anonymous · Answer

right?

anonymous · Answer

sorry i meant y

anonymous · Answer

x does not pass the vertical line test so it is not a function

nincompoop · Answer

directrix · Answer

>> which is a function? 
@kaylalynn

A function f  is the set of ordered pairs (x,y) such that if (x1, y1)  AND (x1,y2)  are elements of f, then y1 = y2.