Define the complex number Z = u^v

In summary, the conversation discusses the representation of complex numbers and how to express them in terms of real numbers. There are multiple ways to do so, such as using the exponential form or converting from the standard form. The inverse conversions are also possible.
  • #1
Bruno Tolentino
97
0
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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  • #2
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
 
  • #3
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].
 
  • #4
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].
 
  • #5
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?
 
  • #6
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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Likes Bruno Tolentino
  • #7
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!
 

1. What is a complex number?

A complex number is a number that contains a real part and an imaginary part. It is usually written in the form a + bi, where a is the real part and bi is the imaginary part with i being the square root of -1.

2. How is a complex number represented?

A complex number is typically represented on a graph known as the complex plane, where the real part is plotted on the horizontal axis and the imaginary part on the vertical axis.

3. How do you define a complex number Z = u^v?

The complex number Z = u^v is defined as the result of raising the complex number u to the power of the complex number v. This can be written as Z = u^v = e^(v*ln(u)), where e is the base of the natural logarithm and ln(u) is the natural logarithm of u.

4. What is the modulus of a complex number?

The modulus of a complex number is the distance of the complex number from the origin on the complex plane. It is calculated by taking the square root of the sum of the squares of the real and imaginary parts, and is denoted by |Z|.

5. What is the conjugate of a complex number?

The conjugate of a complex number is another complex number that has the same real part but the opposite sign for the imaginary part. It is denoted by Z* and is calculated by changing the sign of the imaginary part of the complex number.

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