00:01
In this question, we are given two contours.
00:03
I mean, the first guy is called triangle abc.
00:09
Ok.
00:10
This is a complex plan.
00:12
Real part, imaginary part.
00:15
A is equal to 0.
00:17
B is equal to 1 plus i.
00:19
C is equal to negative 2.
00:22
Here is our triangle.
00:24
We want to do the integral in this way.
00:28
And second, we're given a circle centered at i.
00:32
I.
00:34
Let's call this circle o, the center of that i with radius 2.
00:42
So it will be a circle like that.
00:47
Then we're going to do the integral on this triangle, z bar dz, and the integral over the circle, z bar dz.
01:00
For the triangle, we can separate this integral into three pieces.
01:05
Is integral ab z bar dz for convenience.
01:14
Straight into 3pc plus bc plus ca z bar dz.
01:23
Okay, for the circle, things will be easier because it's very easy for us to parameterize the circle.
01:30
Let's try to do it first.
01:33
Ab is a straight line from 0 to 1 plus i, so it can be parameter is the right side t times one plus i t from zero to one so z bar on ab is equal to t times one minus i and dzt dzt is equal to one plus i dt okay bc is a straight line from from 1 plus i to negative 2.
02:12
So it'd be pretty easy to write that.
02:14
1 plus i plus t times negative 2 minus 1 minus i, which is equal to 1 plus i plus t times negative 3 negative i.
02:27
So the conjugate of z on a, b is equal to 1 minus i plus t t times negative 3 plus i and dz is equal to negative 3 minus i dt.
02:49
Ok, along ca, this will be easier because we don't have the imaginary part.
02:56
Ca can be parameterized as negative 2 plus 2i, or 2t.
03:02
I mean, all t's, all t's of all just go from 0 to 1.
03:06
The same for here and here.
03:10
And z bar t is equal to the same thing because there is no imaginary part.
03:18
And dzt is equal to 2dt.
03:22
Okay, use all the information about this integral.
03:26
It can be written as the first, along a, b, it goes from 0 to 1.
03:32
T times 1 minus i, dz, 1 plus i, dt...