00:01
Okay, so let's see what we can learn here.
00:03
We have several quadratic functions that are graphed and other quadracts because their graphs are parabolas.
00:10
We have a lot of them, a lot of things going on here.
00:13
We want to look at the intercepts, the vertex maximum or minimum and range of one of these graphs.
00:21
Let's look at f, the graph of f.
00:27
So we have this parabola.
00:28
It opens up.
00:29
So that will have an impact on what.
00:34
Whether we have a maximum or minimum.
00:36
Let's start, though, with the intercepts.
00:38
We'll find the x intercepts and the y intercepts, meaning where it crosses the x axis and the y axis.
00:45
So the x intercepts, i &t for intercepts.
00:50
Let's see.
00:51
This graph crosses the x axis at these points right here, this point here, and here.
01:00
And so our x intercepts would be, let's see, read the coordinate.
01:05
Start at the origin, go left 1, so that's x equals negative 1, and the y coordinate would be 0.
01:13
You have negative 1, 0, that is one of the x intercept.
01:17
There's another one.
01:18
That would be 3 to the left, so that would be negative 3, and the y coordinate is 0.
01:26
And this format for the x intercept will always be some x value, comma, zero, because on the x -axis, all the y value is always 0.
01:38
Let's find, speaking of why, let's find the y intercept.
01:41
We have the vertical axis, the y axis here, our y intercept that happens where it crosses or hits the y axis.
01:51
And so the coordinates for this, the y intercept, what is the coordinates? what are the coordinates? zero is the x coordinate because starting at the origin, no left or right.
02:04
You just go up in the positive of y direction three units.
02:09
So 0 .3 is the y intercept.
02:12
Because these are functions, you know, all four of these graphs are, they pass the vertical line test.
02:19
Also, there's only ever going to be one y intercept of a function because if x equals zero is paired with multiple y values, then it would fail the vertical line test and would not be a function.
02:30
That's a different problem for a different day.
02:33
Let's look at the vertex.
02:34
You might also think of this as the turning point.
02:38
And there's a lot of symmetry that happens with the vertex.
02:41
Let's see.
02:42
The vertex would be the point right here, sort of in the middle of this parabola.
02:50
And the coordinates of the vertex, coordinates of the vertex, let's see, we go 2 to the left.
02:57
So that's negative x direction and 1 down, negative y direction.
03:02
So it would be negative 2, negative 1.
03:05
The vertex are given by the coordinates negative 2, negative 1.
03:13
Through the vertex, we have our axis of symmetry, our axis of symmetry.
03:21
Now i didn't draw this graph, you know, amazingly, but if i were to, you know, you could fold the, i guess the screen across the axis of symmetry, these points on either side, they're the same distance away, they would line up...