00:01
Okay, we have some integrals.
00:02
We're not supposed to evaluate the integrals.
00:04
We're just supposed to figure out what coordinate system to use.
00:10
Here's the first one.
00:12
So totally cartesian.
00:17
Everything is cartesian in it, and there's no special limits or anything like that.
00:21
So that's our best choice.
00:27
This one's also cartesian, but i noticed something really interesting about it.
00:32
If you do the x integral, you get log of x, that we're gonna then evaluate at zero and y squared.
00:40
But it's that zero makes it an improper integral, and its value is actually infinite.
01:01
So this one, it looks like it might be cartesian, except for the fact that we have this limit on x squared plus y squared, which we know is the square of the cylindrical radius.
01:17
So i'm gonna say cylindrical coordinates.
01:21
That makes life a lot easier, because actually in cartesian coordinates, we'd get limits on, say, x that involve a square root of four minus y squared.
01:43
And so that's unpleasant and unnecessary.
01:49
If you do it in cylindrical coordinates, it's a lot easier...