Simplifying the factors of a complex number's imaginary part

In summary, the conversation discusses the possibility of simplifying the imaginary part of a complex-valued function composed of multiple factors, each with known real and imaginary components and the ability to take on the value of their conjugate. However, there is no known formula to make this simplification easier and the best approach may be to write each complex number as an amplitude and phase factor and take the product of the amplitudes with the sine of the total phase.
  • #1
TheCanadian
367
13
My question boils down to wondering if there is a way to simplify the imaginary part of a complex-valued function composed of n factors if the real and imaginary component for each of the factors is known but the factors may take on the value of their conjugate as well.

For example, is there a known way to simplify:

## Q = \Im (A^* \times B \times C^* \times D^*) ##

where A, B, C, and D are each complex numbers themselves with known real and imaginary parts, ##\Im ## is taking the imaginary part, and ## ^* ## corresponds to taking the complex conjugate of the complex number. Ideally, I'm wondering if there is known a way to simplify Q into another equivalent form such as

## Q = \Im (A) \Im (B^* \times C \times D) ##.

I've attached my attempt at simplifying the imaginary part of a complex number composed of 3 factors that are themselves each complex-valued. It does feel like there is some kind of pattern but I'm not seeing and am oblivious to how it extends for larger systems and for complex conjugates taken at arbitrary positions. Would any of you happen to know if there's a known way to factorize such numbers?
 

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  • #2
There is no formula that would make it easier. You can write all numbers as ##A=A_R+iA_I## and so on and then make a long list of summands that contribute to the imaginary part, e. g. ##A_RB_RC_RD_I + A_RB_RC_ID_R + \dots## (in total 8 components) but that is not very useful. If you know the numbers, where is the problem with just multiplying them?
Complex conjugation just changes the sign of the imaginary part, apart from that nothing happens so it is easy to take into account.

In your attached screenshot, two summands with c2 got lost.
 
  • #3
One suggestion is to write each complex number as an amplitude and phase factor. i.e. ## A=A_o e^{i \phi_A} ## etc. To get the final imaginary part, that is just a product of the amplitudes, ## A_o B_o C_o D_o ##, etc., multiplied by ## \sin{\phi_{total}} ##. (using Euler's formula). (## \phi_{total} ## is the sum of the phase factors.) Perhaps this is what you are looking for? (Note: A complex conjugate simply puts a minus sign on the phase of the number.)
 
Last edited:

What is a complex number's imaginary part?

A complex number is a number that contains both a real part and an imaginary part. The imaginary part is a multiple of the imaginary unit, denoted by "i", which is defined as the square root of -1. The imaginary part is represented by adding a coefficient in front of "i". For example, in the complex number 3+4i, the imaginary part is 4i.

Why is it important to simplify the factors of a complex number's imaginary part?

Simplifying the factors of a complex number's imaginary part allows for easier manipulation and calculation of the number. It also helps in identifying patterns and relationships between complex numbers.

How do you simplify the factors of a complex number's imaginary part?

To simplify the factors of a complex number's imaginary part, you need to factor out the imaginary unit "i" and any common factors between the coefficient and the remaining real part. This will result in a simpler form of the imaginary part.

What are the benefits of simplifying the factors of a complex number's imaginary part?

As mentioned before, simplifying the factors of a complex number's imaginary part allows for easier manipulation and calculation of the number. It also helps in identifying patterns and relationships between complex numbers. Additionally, it can make the number more visually appealing and easier to understand.

Can the factors of a complex number's imaginary part be simplified to a negative number?

Yes, the factors of a complex number's imaginary part can be simplified to a negative number. For example, if you have the complex number 3-4i, the imaginary part can be simplified to -4i. This is because multiplying -1 with "i" results in -i, which when combined with the coefficient -4, gives us -4i.

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