00:01
All right, so for these problems, we're going to be using what we know about the first and second derivative in the function itself to answer six questions about a graph.
00:09
You'll find the graph in your textbook.
00:11
This is the graph for number six.
00:13
The first thing we're trying to figure out is the behavior.
00:16
Behavior means is the function increasing or decreasing? are the y values getting bigger or are the y values getting smaller as the x values go left to right? so looking at our graph, what we'll see is from the starting point at about negative 3 .5, the graph increases until it gets to the maximum at about 0 .5.
00:43
So we could say it's increasing from negative 3 .5 to negative 0 .5.
01:01
Now there's some contention as to whether or not to include the actual starting value and the endpoints, but it does make sense to include them because the definition of increasing and decreasing is with respect to the points around it.
01:19
So with respect to the points around it, if the next point is higher than the point you're at or then the function is increasing.
01:26
If in a neighborhood it is bigger than the point before it, then we say that the function is, you know, it's bigger than the point before it, then we say that the function is increasing.
01:35
And the function decreases.
01:36
Now we don't know if it goes on forever to the right or if it stops at that last x value.
01:42
It looks like we should assume it continues forever.
01:46
So that's what i'm going to do here.
01:48
So the function decreases for the rest of its existence.
01:55
So it's going to decrease from negative 0 .5 to infinity.
02:03
All right.
02:04
So our relative extreme, we only have one where the function changes from increasing to decreasing, like here, increasing to decreasing, we'll have a maximum if f of x is zero or if f of x is undefined, which would be a sharp point.
02:17
Our function doesn't have a sharp point.
02:19
It has a nice defined maximum.
02:22
So we do have a relative maximum, and it's at about negative 0 .5 and like about 5 .1...