Pre-calculus help..........?

Question

Today was my first day back to school and we got a little pre cal homework. Sadly I don't remember how to do any of these kinds of things from algebra 2 so I need a little help on a couple problems. the first problem says to determine whether the equation represents y as a function of x and gives x(squared) + y(squared) = 4

Any help on solving this problem would be appreciated, please show work and give an explanation so that I can proceed to do the rest on my own.

Answer 1

No it's not a function. It's a circle with radius of 2, and so it doesn't pass the vertical line test (where you need one y value for each x value and no more) and so is not a function.

Answer 2

that equation forms a circle. it is not a function cuz it doesn't past the vertical line test. a function is only a function when for every imput (x) there is only one output (y). in a circle, one imput can have two outputs and therefore it is not a function.

Answer 3

when in doubt put 0 =]

Answer 4

If there is a y(squared) then it is not a function. So no work would be needed... if there is a y squared then some of the graph would be on the negative and some would be on the positive and it would not pass the verticle line test.