Principal root of a Complex Number

In summary, the problem asks to find all the fourth roots of the complex number (-8 - 8√3i)^1/4 and exhibit them as vertices of a square. The four roots are ±(√3 - i) and ±(1 + √3i) and the principal root is the one with the least standardized argument.
  • #1
DEMJ
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Homework Statement


Find all the roots in rectangular coordinates, exhibit them as vertices of certain squares, and point out which is the principal root.


The Attempt at a Solution



The problem is [tex](-8 -8\sqrt{3}i)^{\frac{1}{4}}[/tex] and I found the four roots easily to be

[tex]\pm(\sqrt{3} - i), \pm(1 + \sqrt{3}i)[/tex]. So when it says to exhibit them as vertices of certain squares does this mean I should just graph the four points? and it should be a square.

Also as for which point is the principal root I have no clue. I am guessing it has something to do with principal argument but I am having trouble finding much information on principal roots.
 
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  • #2
For any non-zero complex number, its fourth roots are arranged on the vertices of a square. You are being asked to verify this for the given number.

If I'm not mistaken, the principal root is the root whose standardized argument is least.

--Elucidus
 

1. What is the principal root of a complex number?

The principal root of a complex number is the value that, when raised to a certain power, equals the original complex number. It is also known as the principal root or principal value of a complex number.

2. How do you find the principal root of a complex number?

To find the principal root of a complex number, you can use the formula z^(1/n), where z is the complex number and n is the root you are trying to find. This formula can be simplified using polar coordinates or De Moivre's theorem.

3. What is the difference between the principal root and other roots of a complex number?

The principal root is the only root of a complex number that falls within the first quadrant of the complex plane. Other roots of a complex number can be found by rotating the principal root around the origin in increments of 2π/n, where n is the root you are trying to find.

4. Can the principal root of a complex number be a real number?

Yes, the principal root of a complex number can be a real number if the complex number itself is a positive real number. In this case, the principal root is simply the positive square root of the original number.

5. Why is the principal root of a complex number important in mathematics?

The principal root of a complex number is important because it allows us to simplify complicated equations involving complex numbers. It also helps us visualize and understand the properties of complex numbers on the complex plane.

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