Define the complex number Z = u^v

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Discussion Overview

The discussion revolves around defining a complex number \( z \) in terms of two variables \( u \) and \( v \), specifically exploring how to express \( u \) and \( v \) in terms of the polar representation of \( z \) given by \( z = r \exp(i \theta) \). The conversation includes attempts to relate these variables to Cartesian coordinates as well.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants inquire how to express \( u \) and \( v \) in terms of \( r \) and \( \theta \) from the equation \( z = r \exp(i \theta) \).
  • One participant suggests that \( u \) and \( v \) could be defined as \( u = r \cos(\theta) \) and \( v = r \sin(\theta) \), but questions whether this aligns with the original intent of expressing \( z \) as \( u^v \).
  • Another participant proposes a solution where \( u = r e^{i\theta} \) and \( v = 1 \), noting that there are infinite possibilities for defining \( u \) and \( v \).
  • Some participants express confusion regarding the definitions of \( u \) and \( v \), with one questioning if they refer to the real and imaginary parts of a complex function.
  • There is a suggestion that \( z \) can also be expressed in terms of Cartesian coordinates \( x \) and \( y \), with a participant attempting to derive relationships between these variables.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions of \( u \) and \( v \) or how to express them in terms of \( r \) and \( \theta \). Multiple competing views and interpretations remain present throughout the discussion.

Contextual Notes

Some participants highlight the ambiguity in the definitions of \( u \) and \( v \), and there are unresolved questions about the relationship between these variables and the standard forms of complex numbers.

Bruno Tolentino
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If I define the complex number z = r exp(i θ) how z = uv, so, how to express u and v in terms of r and θ?

u(r, θ) = ?
v(r, θ) = ?

And the inverse too:

r(u, v) = ?
θ(u, v) = ?
 
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Bruno Tolentino said:
If I define the complex number z = r exp(i θ) how z = uv, so, how to express u and v in terms of r and θ?

u(r, θ) = ?
v(r, θ) = ?

And the inverse too:

r(u, v) = ?
θ(u, v) = ?
Have you looked at this article?

http://mathworld.wolfram.com/ComplexExponentiation.html
 
I don't understand your question. You ask, apparently, for z in terms of "u" and "v" but have not said what "u" and "v" are! Are you referring to the representation of a complex function as "z(x+ iy)= u(x,y)+ iv(x,y)" where u and v are real valued function of the real variables x and y? If so then [itex]z= re^{i\theta}[/itex] is NOT "[itex]u^v[/itex]". [itex]z= re^{i\theta}= r(cos(\theta)+ isin(\theta)[/itex] so that [itex]u= r cos(\theta)[/itex] and [itex]v= r sin(\theta)[/itex].
 
Bruno Tolentino said:
If I define the complex number z = r exp(i θ) how z = uv, so, how to express u and v in terms of r and θ?

u(r, θ) = ?
v(r, θ) = ?

And the inverse too:

r(u, v) = ?
θ(u, v) = ?
I'm not sure what you are looking for, but [itex]u=re^{i\theta},\ v=1[/itex] works.
However there are an infinite number of possibilities, by using [itex]u=r^ne^{ni\theta}\ and\ v=\frac{1}{n}[/itex].
 
Z is a complex number, u is a real number and v is a real number too. Is just another way of express the complex numbers...

So, is possible convert the expression z = x + i y in z = uv ? Is possible express u and v in terms of x and y?
 
Bruno Tolentino said:
So, is possible convert the expression z = x + i y in z = uv ? Is possible express u and v in terms of x and y?
Well, let's try. You know that [itex]z=x+iy[/itex] can also be expressed as [itex]z=re^{i\phi}[/itex], where [itex]r=\sqrt{x^{2}+y^{2}}[/itex] and [itex]\phi = \arcsin(\frac{y}{r})[/itex]. Therefore, we obviously have [itex]z=e^{\ln r}\cdot e^{i\phi}= e^{\ln r + i\phi}[/itex]. ...
 
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Yeah! I thought this... but, I was unsatisfied com this 'conversion' and so I posted my doubt here because the most experiente could see something better...

Anyway! Thank you!
 

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