Complex Series converfence proof

In summary, we can use the Cauchy-Riemann equations for each term in the sequence u(z) and then take the sum of each CR equation for the infinite sequence to show that the sum of u(z) is analytic in the entire complex plain. This is possible because we already know that u(z) is uniformly convergent and we can perform term by term integration and differentiation for each term u_n(z).
  • #1
stihl29
25
0

Homework Statement


Suppose we already know series [tex]u(z) = \displaystyle\sum_{n=0}^\infty u_n(z)[/tex]is uniformly convergent in the entire complex plain and we can perform term by term integration and differentation each term [tex]u_n(z)[/tex] in the analyitic function. use cauchy-riemann equations to show that the sum of u(z) is analytic in the entire complex plain.


Homework Equations


[tex]$\displaystyle \frac{\partial u}{\partial x} = \frac{\partial v}{\partial y},\quad
\frac{\partial u}{\partial y} = -\frac{\partial v}{\partial x},$[/tex]


The Attempt at a Solution


My only guess at a solution would be to use the CR equations for each term in the sequence. ??
 
Physics news on Phys.org
  • #2
$\displaystyle \frac{\partial u_n}{\partial x} = \frac{\partial v_n}{\partial y},\quad\frac{\partial u_n}{\partial y} = -\frac{\partial v_n}{\partial x},$Then take the sum of each CR equation for the infinite sequence. $\displaystyle \sum_{n=0}^\infty\frac{\partial u_n}{\partial x} = \sum_{n=0}^\infty\frac{\partial v_n}{\partial y},\quad\sum_{n=0}^\infty\frac{\partial u_n}{\partial y} = \sum_{n=0}^\infty -\frac{\partial v_n}{\partial x}.$But that doesn't seem right. Can someone help?
 

1. What is a complex series convergence proof?

A complex series convergence proof is a mathematical technique used to determine whether a series of complex numbers converges or diverges. It involves analyzing the behavior of the terms in the series to determine if they approach a finite limit or if they oscillate between values.

2. Why is it important to prove the convergence of a complex series?

Proving the convergence of a complex series is important because it ensures that the series has a well-defined sum. This is crucial in many mathematical applications, as it allows for the use of series to approximate functions and solve equations.

3. What are some common methods used in complex series convergence proofs?

Some common methods used in complex series convergence proofs include the comparison test, ratio test, root test, and the integral test. These methods involve comparing the given series to a known convergent or divergent series or using properties of integrals to determine convergence.

4. Can a complex series converge at some points and diverge at others?

Yes, a complex series can converge at some points and diverge at others. This is known as conditional convergence. It occurs when the series converges only when certain conditions are met, such as when the terms are arranged in a specific order.

5. Are there any other factors that can affect the convergence of a complex series?

Yes, there are other factors that can affect the convergence of a complex series. These include the choice of starting point, the number of terms included in the series, and the behavior of the terms themselves. It is important to carefully consider all of these factors when proving the convergence of a complex series.

Similar threads

Replies
4
Views
648
  • Calculus and Beyond Homework Help
Replies
19
Views
981
  • Calculus and Beyond Homework Help
Replies
27
Views
740
  • Calculus and Beyond Homework Help
Replies
1
Views
965
  • Calculus and Beyond Homework Help
Replies
8
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
Replies
16
Views
2K
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
3K
Back
Top