00:01
In this question, we want to find the area bounded by this curve in the first quadrant from x equals to 1 to x equals to 4.
00:09
Now, in a general case, if we have a function, y equals to fx, and we want to find the area under the curve from x equals to a to b.
00:22
The concept is that we just take a small strip over here.
00:26
We will call this with dx, a small change in the x.
00:31
Now the y value over here, we'll just call it y.
00:38
So you can see that the area of this small strip is y -d -x.
00:45
Now we're just going to sum it up to get the actual area.
00:51
I'm just going to sum up from the interval a to b.
00:55
So because this is a continuous summation, so it will be the integration sign a to b, y, d -x.
01:02
And this will be the total area that we want to find.
01:10
So in this case, when we want to find area for this curve in the first quadrant, it will be from 1 to 4, y, dx.
01:25
Now, y is actually long x, the whole thing, square, divided by x, dx.
01:34
Okay, i'm more used to writing long x, the whole thing, square like this.
01:42
Okay, now, there are a couple of times.
01:45
Techniques to integrate this expression here, but in this topic, we're going to be using substitution method and the integration power rule.
01:56
So for integration power rule, if we're integrating u to power n, we respect to u...