How to Prove z^n + 1/z^n = 2cos(nθ) Using Induction?

In summary, the conversation discusses proving a mathematical statement involving non-real complex numbers and trigonometric functions. The proposed solution involves using induction and treating cos(theta) as a constant number. The suggestion of expressing z as e^(i*theta) is offered as a way to simplify the problem.
  • #1
mikee
30
0

Homework Statement

If z is a non-real complex number such that z+1/z=2costheta, prove that z^n+1/z^n=2cosntheta for any posistive integer n



Homework Equations


I think the process of induction would work, but I am not quite sure how to do that with all of the unknowns, would i just treat costheta as a constant number


The Attempt at a Solution

 
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  • #2
mikee said:

Homework Statement

If z is a non-real complex number such that z+1/z=2costheta, prove that z^n+1/z^n=2cosntheta for any posistive integer n



Homework Equations


I think the process of induction would work, but I am not quite sure how to do that with all of the unknowns, would i just treat costheta as a constant number


The Attempt at a Solution


Apparently
[tex]
z=e^{i\theta}
[/tex]
...does that help?
 
  • #3
If z=cosx+isinx, what is z^n?
 

FAQ: How to Prove z^n + 1/z^n = 2cos(nθ) Using Induction?

What are complex numbers?

Complex numbers are numbers that have both a real and imaginary part. They are written in the form a + bi, where a is the real part, b is the imaginary part, and i is the imaginary unit equal to the square root of -1.

How are complex numbers used in science?

Complex numbers are used in many fields of science, including physics, engineering, and mathematics. They are particularly useful in solving problems involving electrical circuits, fluid dynamics, and quantum mechanics.

What is induction?

Induction is a method of mathematical proof that involves using a base case and a general rule to prove that a statement is true for all values. It is commonly used in proving statements about infinite sets and series.

How are complex numbers and induction related?

Complex numbers and induction are related in that complex numbers can be used to prove mathematical statements using induction. For example, complex induction is used to prove the fundamental theorem of algebra, which states that every polynomial equation has at least one complex root.

Can complex numbers and induction be applied in other areas besides mathematics?

Yes, complex numbers and induction can also be applied in other areas such as computer science and economics. In computer science, complex numbers are used in signal processing and cryptography. In economics, complex numbers are used in modeling stock market behavior and analyzing economic systems.

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