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
Polar Form of Complex Numbers
3:31 minutes
Problem 19
Textbook Question
In Exercises 11–26, plot each complex number. Then write the complex number in polar form. You may express the argument in degrees or radians. −3
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1
Step 1: Identify the complex number. In this case, the complex number is \(-3\), which can be written as \(-3 + 0i\).
Step 2: Plot the complex number on the complex plane. The real part is \(-3\) and the imaginary part is \(0\), so the point is located on the real axis at \(-3\).
Step 3: Determine the modulus (magnitude) of the complex number using the formula \(|z| = \sqrt{a^2 + b^2}\), where \(a\) is the real part and \(b\) is the imaginary part.
Step 4: Calculate the argument (angle) of the complex number. Since the number is on the negative real axis, the argument is \(\pi\) radians or \(180^\circ\).
Step 5: Write the complex number in polar form using the formula \(z = r(\cos \theta + i\sin \theta)\), where \(r\) is the modulus and \(\theta\) is the argument.
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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 imaginary part. In this context, the complex number -3 can be represented as -3 + 0i, indicating that it lies on the real axis of the complex plane.
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Polar Form of Complex Numbers
The polar form of a complex number expresses it in terms of its magnitude (or modulus) and angle (or argument). It is represented as r(cos θ + i sin θ) or r e^(iθ), where r is the distance from the origin to the point in the complex plane, and θ is the angle formed with the positive real axis. For -3, the polar form can be calculated using its modulus and argument.
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Magnitude and Argument
The magnitude of a complex number is the distance from the origin to the point in the complex plane, calculated using the formula r = √(a² + b²). The argument is the angle formed with the positive real axis, which can be found using the arctangent function. For the complex number -3, the magnitude is 3, and the argument is π radians (or 180 degrees), as it lies on the negative real axis.
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