Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
11. Graphing Complex Numbers
Powers of Complex Numbers (DeMoivre's Theorem)
Problem 70
Textbook Question
Textbook QuestionIn Exercises 69–76, find all the complex roots. Write roots in rectangular form. If necessary, round to the nearest tenth. The complex fifth roots of 32 (cos 5π/3 + i sin 5π/3)
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Complex Numbers
Complex numbers are numbers that have a real part and an imaginary part, expressed in the form a + bi, where 'a' is the real part and 'b' is the coefficient of the imaginary unit 'i'. Understanding complex numbers is essential for solving problems involving roots, especially in trigonometric contexts where angles and magnitudes are involved.
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De Moivre's Theorem
De Moivre's Theorem states that for any complex number in polar form r(cos θ + i sin θ), the nth roots can be found using the formula r^(1/n)(cos(θ/n + 2kπ/n) + i sin(θ/n + 2kπ/n)), where k is an integer from 0 to n-1. This theorem is crucial for finding complex roots, as it simplifies the process of extracting roots from complex numbers.
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Rectangular Form
Rectangular form refers to the standard way of expressing complex numbers as a + bi. When finding complex roots, it is often necessary to convert from polar form (which uses magnitude and angle) to rectangular form for clarity and ease of interpretation. This conversion involves calculating the real and imaginary components based on the cosine and sine of the angle.
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Master Powers Of Complex Numbers In Polar Form (DeMoivre's Theorem) with a bite sized video explanation from Nick Kaneko
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