Roots of Unity and Complex Numbers

Roots of Unity and Complex Numbers

Assessment

Interactive Video

Mathematics

11th - 12th Grade

Hard

Created by

Olivia Brooks

FREE Resource

The video tutorial explores the roots of unity, emphasizing their importance in understanding complex numbers and their relation to real numbers. It introduces omega, a complex number, and demonstrates how to use De Moivre's Theorem to raise it to integer powers. The tutorial further proves that omega to the power of k is a solution to the equation z^9 = 1. It concludes by showing how factorization can be used to solve polynomial equations, specifically demonstrating that a given polynomial in omega equals negative one.

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10 questions

Show all answers

1.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is one of the surprising aspects of the roots of unity?

They are irrelevant to complex numbers.

They provide insights into real numbers through complex numbers.

They are only used in theoretical mathematics.

They are only applicable to real numbers.

2.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What does the notation 'cis' represent in the context of complex numbers?

cosine plus sine

cosine plus imaginary sine

cosine and sine

cosine and imaginary sine

3.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the significance of omega^k in the given problem?

It is a solution to the equation z^9 = 1.

It is unrelated to the equation.

It is a real number.

It is a random complex number.

4.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

Which theorem is used to raise a complex number to an integer power?

De Moivre's Theorem

Fermat's Last Theorem

Binomial Theorem

Pythagorean Theorem

5.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the periodicity of the trigonometric functions used in the solution?

Every pi radians

Every 4 pi radians

Every 2 pi radians

Every 3 pi radians

6.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the significance of k being an integer in the solution?

It ensures the periodicity of trigonometric functions.

It makes the equation unsolvable.

It has no significance.

It complicates the solution.

7.

MULTIPLE CHOICE QUESTION

30 sec • 1 pt

What is the main goal of part B in the problem?

To find the value of omega

To prove a polynomial equation equals -1

To solve for z in a different equation

To demonstrate the use of De Moivre's Theorem

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