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Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 89

In calculus, it can be shown that e^(iθ) = cos θ + i sin θ. In Exercises 87–90, use this result to plot each complex number. -e^-πi

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Recall Euler's formula: \(e^{i\theta} = \cos \theta + i \sin \theta\). This expresses a complex number on the unit circle in terms of an angle \(\theta\).
Identify the angle \(\theta\) in the expression \(-e^{-\pi i}\). Notice that \(e^{-\pi i} = \cos(-\pi) + i \sin(-\pi)\) by Euler's formula.
Calculate \(e^{-\pi i}\) using the cosine and sine values: \(\cos(-\pi) = \cos \pi\) and \(\sin(-\pi) = -\sin \pi\). Substitute these values to get the complex number.
Multiply the result by \(-1\) to account for the leading negative sign in \(-e^{-\pi i}\). This will reflect the point across the origin in the complex plane.
Plot the resulting complex number on the complex plane, where the real part corresponds to the x-axis and the imaginary part corresponds to the y-axis.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Euler's Formula

Euler's formula states that e^(iθ) = cos θ + i sin θ, linking complex exponentials to trigonometric functions. It allows expressing complex numbers in polar form, facilitating their interpretation as points or vectors in the complex plane.
추천 영상:
6:36
Quadratic Formula

Complex Number Representation in the Complex Plane

Complex numbers can be represented as points or vectors in the complex plane, where the x-axis is the real part and the y-axis is the imaginary part. Using Euler's formula, a complex number can be plotted by interpreting its magnitude and angle (argument).
추천 영상:
4:22
Dividing Complex Numbers

Properties of Exponents and Negative Signs in Complex Numbers

Understanding how to handle negative signs and exponents in complex numbers is essential. For example, -e^(-πi) involves both a negative sign and a complex exponential with a negative angle, affecting the position and direction of the point in the complex plane.
추천 영상:
4:22
Dividing Complex Numbers