Which graph represents a relation that is not a function?
(See Graph Below)
I Think it's option C

Question

Which graph represents a relation that is not a function?
(See Graph Below)
I Think it's option C

anonymous · Answer

attachment

whpalmer4 · Answer

C is sadly not correct.  use the vertical line test.  if at any point a vertical line will cross the curve more than once, it is not a function (because that means at some value of x, there are multiple values of y).

whpalmer4 · Answer

a function is a one-to-one mapping from x to y, so there can be only one value of y at any given value of x.

anonymous · Answer

A?

whpalmer4 · Answer

that's correct — a vertical line drawn anywhere to the left of x = 0 crosses over the graph twice, so the graph in A is not a function.

anonymous · Answer

thank you!

whpalmer4 · Answer

if you get your data in a table, the way you apply this test is to look for having the same x value appear more than once.  for example, the following x y table represents a relation which is not a function

x   y
3   5
2    4
8    1
3    2
-4  0

(x=3 appears twice, with different y values.  not a function)

whpalmer4 · Answer

might also be written like {3,5}, {2,4}, {8,1}, {3,2}, {-4,0}.  still not a function.  you get the idea, I trust!