What is the Log of a Complex Variable?

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Homework Help Overview

The discussion revolves around the logarithm of a complex variable, specifically in the form of z = X + iY. Participants are exploring the properties and representations of this logarithm in a mathematical context.

Discussion Character

  • Exploratory, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the conversion of a complex number into polar form and the implications of this representation on the logarithm function. Questions about the multi-valued nature of the logarithm in the complex plane are raised.

Discussion Status

Some participants have provided insights into the polar form of complex numbers and the logarithmic function, noting its multi-valued characteristic. There is an ongoing exploration of these concepts without a clear consensus on a single interpretation.

Contextual Notes

Participants are considering the periodic nature of the tangent function and how it affects the logarithm's values, indicating a need for clarity on the definitions and assumptions involved in the discussion.

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what is log of z=X+JY?

Thanks
 
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Did you try to find out what it would be??

Here.
 
We can always write x+ iy in "polar form": [itex]x+ iy= re^{i\theta}[/itex] where [itex]r= \sqrt{x^2+ y^2}[/itex] and [itex]\theta= arctan(y/x)[/itex].

Then [itex]ln(x+ iy)= ln(re^{i\theta})= ln(r)+ i\theta[/itex]. Of course, because tangent is periodic, with period [itex]\pi[/itex], ln is not a single-valued function:
[itex]ln(x+ iy)= ln(r)+ i(\theta+ n\pi)[/itex] for n any integer.
 
Thanks
 
ln(x+iy)=ln(r)+i(θ+2*nπ) for n any integer.
 

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