00:01
We want to find the area of the enclosed region, closed by the functions y equals 1 over x, y equals x, and y equals 1 quarter times x.
00:15
So doing a quick sketch shows us that the region is this triangle over here.
00:21
So we do have to figure out what are these three points so that we know what will be our limits of integration.
00:28
So if we label these points 1, 2, and 3, let's take a look at 1 first.
00:37
So this point is very easy.
00:39
It's easy to see it's the origin because this is the intersection of the lines x and 1 quarter x.
00:46
Solving for this tells us x equals 0.
00:52
Let's take a look at the second point.
00:55
This is the intersection of the line x with the function 1 over x.
01:01
Solving for this gives us x squared equals 1, which gives us x is either plus 1 or minus 1.
01:08
But since we're only considering x greater than 0, this tells us that x is equal to 1 is the second point.
01:17
And now if we take a look at the third point, this is going to be the intersection of the line 1 quarter x with the function 1 over x.
01:29
So solving for this, we get x squared equals 4.
01:34
And then again, since x is positive, x is equal to 2.
01:38
So we can label these points over here with 0, x equals 0, x equals 1, and x equals 2.
01:48
So now we want to integrate to figure out the area.
01:53
So let's open up a new page.
01:56
Area is equal to, first we're integrating from 0 to 1...