00:01
Hi there, in this problem r is bounded by y equals natural log 5x, y equals 1, y equals 4 and x equals 0 is rotated about the y axis.
00:09
We have to find the volume of the solid.
00:11
This curve represents y equals natural log 5x.
00:14
These horizontal lines that are dotted represent y equals 1 and y equals 4 and the region is shaded as shown.
00:25
Now rotating this region about the y axis would make a solid so we we firstly consider a very small element of the solid.
00:35
So we write that consider a small element of the solid.
00:48
So we have considered a small element and it is in the form of this.
00:53
So we write that is a disk with thickness d -y.
01:04
It can be seen in the figure.
01:09
So now radius of this disk we have to find.
01:16
Since it is bounded by the curve y equals natural log 5x, so x value can be determined from this curve.
01:25
The curve is y equals natural log 5x...