00:01
This problem gives us six graphs, and it wants us to determine which of the following graphs represent valid functions.
00:06
And to determine if a graph is a function or not, the fastest and the easiest way to do that is to use the vertical line test.
00:14
And the vertical line test is as you drag a vertical line from left to right on your graph, if it is intersecting at one point or no point, then your graph can be considered a function.
00:25
But if it's ever intersecting through two points at the same time or two points or more at the same time, then it's not considered a function because you would have an x value or an input value going to two separate output values, which we can't have for a function.
00:38
So for our first function, looking at the top left, this would be considered a function because it passes the vertical line test.
00:45
At no point as i move a vertical line from left to right am i intersecting at more than one point.
00:49
So this would be considered a function.
00:51
For our next choice down, so we're still on the left side and the left column, but we're looking at the second function down.
00:57
At first it seems like we have a function, but as soon as we get in this middle behavior, we can see we're intersecting at more than one point, in fact, three points at sometimes.
01:06
So that would not represent a function.
01:09
For our furthest graph down on the left column, we have a function because as we go from left to right, again, we see what we saw in the first function, where we're only intersecting at one point.
01:19
So the furthest graph down on the left will be considered a function...