Exploring Holomorphic Functions in Complex Analysis

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In summary, you were told not to use limits and so you used Cauchy-Riemann to show e^z is holomorphic. You also checked e^(-z) to see if it is also holomorphic.
  • #1
Firepanda
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I'm not too sure how to show this. Perhaps if I show d(ez)/dz = ez then does this conclude that ez is holomorphic on all of C?
 
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  • #2
Why does d/dz(e^z)=e^z show e^z is holomorphic? Or at least, why are you saying you aren't sure this shows it's holomorphic?
 
  • #3
I suppose I should be using the cauchy riemann equations then?

I was told not to use limits here so I didn't want to use the base definition of holomorphic-ness.
 
  • #4
Dick said:
Why does d/dz(e^z)=e^z show e^z is holomorphic? Or at least, why are you saying you aren't sure this shows it's holomorphic?

Because in my notes he mentioned the power series
 
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  • #5
Firepanda said:
I suppose I should be using the cauchy riemann equations then?

I was told not to use limits here so I didn't want to use the base definition of holomorphic-ness.

Sure, use Cauchy-Riemann. That's easy enough. Then you'd want to show e^(-z) is also holomorphic. Do you know the sum of holomorphic functions is also holomorphic? If not then you could just directly show cosh(z) is holomorphic using CR.
 
  • #6
i tried to use C-R, but I'm unable to split it up into

U(x,y) or V(x,y)

using z=x+iy into cosh(z)
 
  • #7
Firepanda said:
i tried to use C-R, but I'm unable to split it up into

U(x,y) or V(x,y)

using z=x+iy into cosh(z)

How about e^z? Can you split that up?
 
  • #8
Dick said:
How about e^z. Can you split that up?

exeiy

= ex(cosy + i.siny)

=excosy + i.exsiny

The C-R satisfy this and so it is holomorphic on all of C? so this would immediatly imply cosh(z) is entire?

And I would check if it were true for e-z as well.
 
  • #9
Firepanda said:
exeiy

= ex(cosy + i.siny)

=excosy + i.exsiny

The C-R satisfy this and so it is holomorphic on all of C? so this would immediatly imply cosh(z) is entire?

And I would check if it were true for e-z as well.
Sure, check e^(-z) as well. It's almost the same thing. I'm a little puzzled why you can split e^(z) and e^(-z) up and not cosh(z). You already said cosh(z)=(e^z+e^(-z))/2.
 
  • #10
Dick said:
Sure, check e^(-z) as well. It's almost the same thing. I'm a little puzzled why you can split e^(z) and e^(-z) up and not cosh(z). You already said cosh(z)=(e^z+e^(-z))/2.

ah ye that would make more sense if i did it directly, thanks!
 

1. What is a holomorphic function?

A holomorphic function is a complex-valued function that is defined and differentiable on an open set in the complex plane. It is also known as an analytic function, as it can be represented by a convergent power series.

2. How is a holomorphic function different from a regular function?

A holomorphic function is a function that is defined and differentiable on a complex plane, while a regular function can be defined and differentiable on a real plane. Additionally, a holomorphic function satisfies the Cauchy-Riemann equations, which relate the real and imaginary parts of the function, while a regular function does not have this property.

3. What are some examples of holomorphic functions?

Some examples of holomorphic functions include polynomials, exponential functions, and trigonometric functions. Any function that can be represented by a convergent power series is also a holomorphic function.

4. What is the importance of holomorphic functions in mathematics and science?

Holomorphic functions have many applications in mathematics and science, particularly in complex analysis, which studies the properties and behavior of functions on the complex plane. They are also used in physics, engineering, and other fields to model and solve problems involving complex variables.

5. How are holomorphic functions used in real-world applications?

Holomorphic functions are used in many real-world applications, such as in signal processing, image analysis, and financial modelling. They are also used in computer graphics, as they can be used to represent and manipulate complex shapes and surfaces. In addition, holomorphic functions are used in the design and analysis of electronic circuits and systems.

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