x^2+y^2=1
Decide whether y is a function of x

Question

x^2+y^2=1
Decide whether y is a function of x

anonymous · Answer

someone wanna help a girl out

e.mccormick · Answer

Have you graphed it?  If you look at the graph, then you can try a vertical line test.

anonymous · Answer

no but one sec i'll try it

anonymous · Answer

do i graph it like a circle or line?@e.mccormick

e.mccormick · Answer

A circle!  And because it is a circle, what would that mean for the vertical line test?

anonymous · Answer

it fails it

anonymous · Answer

so it's not a function of x

anonymous · Answer

right @e.mccormick

e.mccormick · Answer

https://www.desmos.com/calculator/rgzrjjypri Exactly!

anonymous · Answer

what about 2x+y=7 @e.mccormick that is a function correct?

e.mccormick · Answer

If you solve that for y, what do you get?  Something that would graph as a line, or another thing that curves and fails the test?

anonymous · Answer

line so yes it is @e.mccormick ty!!!!!!!!!!!!!!!!!!!!!

e.mccormick · Answer

Any line or basic curve that passes the vertical line test is a function.  

Any curve that folds over to the point where it back tracks at all will fail.  Any set of x and y pairs, like $(x_1,y_1),\, (x_2,y_2),\, (x_3,y_3),$ etc. where the same x value has different y values fails.

As you can see, it is just a bunch of really simple tests.  Pass or fail.

Sorry about the reply delays, but the site keeps telling me it is loading.... =/