If a complex converges, then it's conjugate converges.

In summary, the statement is asking to prove that the limit of z_n equals z_0 if and only if the conjugate of z_n equals the conjugate of z_0 as n goes to infinity. This can be shown by using properties of complex conjugates and rewriting the statement as a proof about limits.
  • #1
Unassuming
167
0

Homework Statement



Prove that z_n -> z_0 if and only if ~(z_n) -> ~(z_0) as n goes to infiinity.

~(z_n) is the conjugate of z_n.


Homework Equations





The Attempt at a Solution



|~(z_n) - ~(z_0) | = | ~(z_n) + ~(-z_0)| <=

|~(z_n)| + |~(-z_0) | = |z_n| + |z_0| <=

and I can't come up with much else. It's about the same for the other direction as well.
 
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  • #2
Using a '*' for complex conjugation is more usual than '~'. |z*|=|z|.
|z_n*-z_0*|=|(z_n-z_0)*|=|z_n-z_0|. Use stuff like that. Now write it in the form of a proof about limits.
 
  • #3
Dick said:
Using a '*' for complex conjugation is more usual than '~'.

* looks better after seeing it. I just couldn't think of a way the first time around.
 

Related to If a complex converges, then it's conjugate converges.

1. What is the meaning of "conjugate" in this statement?

"Conjugate" refers to the complex conjugate of a complex number, which involves changing the sign of the imaginary part. For example, the complex conjugate of 3+4i is 3-4i.

2. How do you know if a complex number is convergent?

A complex number is convergent if its real and imaginary parts both approach a finite limit as the independent variable approaches a certain value. In other words, the real and imaginary parts of the complex number must become closer and closer to a constant value as the independent variable gets closer to a specific value.

3. Does the statement apply to all complex numbers?

Yes, the statement "If a complex converges, then it's conjugate converges" applies to all complex numbers, as long as the complex number in question is convergent.

4. Can a complex number converge without its conjugate converging?

No, if a complex number is convergent, then its conjugate must also be convergent. This is because the real and imaginary parts of a complex number are dependent on each other, and if one part is converging, the other part must also be converging in order for the entire complex number to converge.

5. What is the significance of this statement in mathematics?

This statement is important in complex analysis, as it helps to determine whether a function is analytic (differentiable) at a point. If a complex number and its conjugate both converge, then the function is analytic at that point. This statement also has applications in the study of complex series and their convergence.

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