00:01
All right, let's go ahead and solve this problem.
00:04
So we're, as usual, we are asked to evaluate this double integral of curlf.
00:12
F, d .s.
00:13
Okay? it's probably not the best idea to do this straightforwardly because, as you can see, f is already quite involving.
00:23
You have e, you have x, y, x, z, a bunch of cross terms.
00:28
So the curl of that expression is not going to look anything simple.
00:33
And the surface is an ellipsoid, which makes things a little bit even more complicated.
00:40
However, using stokes theorem, we can simplify this problem significantly.
00:44
So let's take a look at what it says.
00:48
First, we're going to be able to say that this is equal to a single integral of through c of f.
00:56
Dot d r so it's a line integral okay so we want to be able to figure out what c is as a projection and then we want to basically parametize that so we can do the calculation all right so the ellipsoid is right here you can find out that y is from zero to four and the projection onto the x z plane is simply a circle so c is a a circle x squared plus z squared is equal to one okay so because of that i would like to choose the parameterization x equals to cosine theta we know that y is equal to zero and z is equal to sine theta.
01:56
Okay.
01:57
Now, where we take a look at the f in terms of the parameterization, we know that y is equal to zero.
02:12
So e to the xy is simply equal to e to the zero, or in other words, one.
02:20
X, z is e to the cosine theta, sine theta.
02:26
It's a little bit alarming, but don't worry.
02:34
And x squared times z is equal to cosine squared times sine.
02:45
Okay, so let's calculate what f...