What is the limit of the complex sequence z_n = [(1+i)/sqrt(3)]^n?

In summary, the limit of z_n = [(1+i)/sqrt(3)]^n as n -> ∞ is 0, as shown by the fact that the absolute value of (1+i)^n goes to 0, which implies that the limit of z_n also goes to 0.
  • #1
DotKite
81
1

Homework Statement



find the limit z_n = [(1+i)/sqrt(3)]^n as n -> ∞.

Homework Equations


3. The Attempt at a Solution

Apparently the limit is zero (via back of the book), but I have no clue how they got that answer.

(1 + i)^n seems to be unbounded, thus i do not see how z_n can go to zero I am lost.
 
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  • #2
DotKite said:

Homework Statement



find the limit z_n = [(1+i)/sqrt(3)]^n as n -> ∞.

Homework Equations


3. The Attempt at a Solution

Apparently the limit is zero (via back of the book), but I have no clue how they got that answer.

(1 + i)^n seems to be unbounded, thus i do not see how z_n can go to zero I am lost.


(1+i)^n is unbounded. But its absolute value is |1+i|^n. What's that??
 
Last edited:
  • #3
Dick said:
(1+i)^n is unbounded. But its absolute value is |1+i|^n. What's that??

|1+i|^n = [sqrt(2)]^n?
 
  • #4
DotKite said:
|1+i|^n = [sqrt(2)]^n?

Sure, so can you show the limit of |z_n| is 0? That would show the limit of z_n is also 0.
 
  • #5
Dick said:
Sure, so can you show the limit of |z_n| is 0? That would show the limit of z_n is also 0.

that is not generally true,

take |(-1)^n + i/n| which converges to 1

{(-1)^n + i/n} does not converge.
 
  • #6
DotKite said:
that is not generally true,

take |(-1)^n + i/n| which converges to 1

{(-1)^n + i/n} does not converge.
But it is true if the limit is zero. ##|z_n| \rightarrow 0## if and only if ##z_n \rightarrow 0##.
 
  • #7
oh i see
 

What is a limit of a complex sequence?

A limit of a complex sequence is the theoretical value that a sequence of complex numbers approaches as the number of terms in the sequence increases. In simpler terms, it is the value that the terms in the sequence get closer and closer to, but may never actually reach.

How is the limit of a complex sequence calculated?

The limit of a complex sequence can be calculated by finding the limit of both the real and imaginary parts of the sequence separately. If both limits exist, then the limit of the complex sequence is the complex number formed by combining the real and imaginary limits.

What is the importance of studying the limit of a complex sequence?

Studying the limit of a complex sequence allows us to understand the behavior and properties of sequences of complex numbers. It also has practical applications in areas such as signal processing, electrical engineering, and physics.

What are some common methods for finding the limit of a complex sequence?

Some common methods for finding the limit of a complex sequence include using the definition of a limit, the squeeze theorem, and the ratio test. Other methods such as L'Hôpital's rule and the Cauchy product can also be used in certain cases.

What are some common misconceptions about the limit of a complex sequence?

One common misconception is that the limit of a complex sequence must be a complex number. In reality, the limit may also be infinity or not exist at all. Another misconception is that the limit of a complex sequence is always equal to the last term in the sequence, when in fact this is not always the case.

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