00:01
Volume where when this region is rotated about the y axis.
00:06
So let's get a picture of this thing.
00:08
When x is zero, y is one.
00:12
When x is one, y is one half.
00:17
When x is four, y is one -third.
00:24
Okay, i'll buy it.
00:27
Because it looks like there's a vertical asthma toad over here at x equals negative one.
00:32
So it comes down like this, except i'm going to miss.
00:37
Okay, it comes down like this.
00:42
All right, x equals zero.
00:44
That's this.
00:45
X equals four, that's here.
00:47
And y equals zero, that's this.
00:49
Okay, so we've got this little thingy right here.
00:52
We're going to send it around the y -axis.
00:57
Okay, if we do disks, then this disc and this disc don't have the same...