Question

In a formula how do determine if y is a function of x?
y=x^2+or-3

Answer 1

Hmm I think if we have a \(\large \pm\) in our equation, it's always going to fail the vertical line test.
I could be wrong though, I'd have to try and think of an example.

\[\Large y=x^2\pm3\]
This function equals\[\Large y=x^2+3 \qquad\text{and}\qquad y=x^2-3\]

Answer 2

https://www.desmos.com/calculator/gc28rtnd73

Answer 3

If you check out the link I provided, you can see both parts of the function graphed.
This one would fail the vertical line test, right? :o

Answer 4

So if it fails the vertical line test then it can't be a function?

Answer 5

then y can't be a function of x, correct :)

Answer 6

Thanks!