is y a function of x?
y=x^2
what's a good website where i can graph
2007-06-20 10:44:35 · 6 answers · asked by lost 2 in Science & Mathematics ➔ Mathematics
this graph is a parabola.
give a value to x, solve for y
x y
1 1
2 4
3 9
-1 1
-2 4
-3 9
2007-06-20 10:48:53 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Here's a good thing to remember:
_Any_ time you have an equation where:
1. the left side is "y" (all by itself), and
2. the right side has some "x"'s in it, and
3. the right side has NO "y"'s, and
4. the right side does not have any "±" symbols:
then YES, y is a function of x. ALWAYS.
The equation you gave satisfies this condition. So y is a function of x.
But note that it's possible to have an equation that does NOT look the way I described, but in which y is still a function of x. So the test I gave can prove that something IS a function, but it can't prove that something is NOT a function.
Examples:
y = 35*sqrt(x^15 - 2x²) ...it's a function.
x² + y² = 49 ...it's not a function
3y + x = 4y - 9 ...it's a function (it can be rewritten as: "y = x+9")
2007-06-20 11:09:18 · answer #2 · answered by RickB 7 · 0⤊ 0⤋
When looking at equations, if you do not see the y raised to an even power or a +/- sign (plus AND minus ) dicectly before the x variable, then the relation is a function.
2007-06-20 10:51:45 · answer #3 · answered by gfulton57 4 · 0⤊ 0⤋
A great online graphing site is http://www.walterzorn.com/grapher/grapher_e.htm Enter your function (here - x^2) and it will graph it for you for the limits of x and y you specify!
2007-06-20 10:49:36 · answer #4 · answered by Carol612 1 · 0⤊ 0⤋
yes.
x=+-1 y=1
x=+-2 y=4
x=+-3 y=9
x=+-4 y=16
http://library.thinkquest.org/2647/media/evenxsqr.gif
2007-06-20 10:50:57 · answer #5 · answered by Anonymous · 0⤊ 0⤋
help you
2007-06-20 10:54:09 · answer #6 · answered by Anonymous · 0⤊ 0⤋