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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 87

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/4)

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Recognize that the expression \(e^{\frac{\pi i}{4}}\) can be rewritten using Euler's formula: \(e^{i\theta} = \cos \theta + i \sin \theta\). Here, \(\theta = \frac{\pi}{4}\).
Substitute \(\theta = \frac{\pi}{4}\) into Euler's formula to express the complex number as \(\cos \left( \frac{\pi}{4} \right) + i \sin \left( \frac{\pi}{4} \right)\).
Calculate the values of \(\cos \left( \frac{\pi}{4} \right)\) and \(\sin \left( \frac{\pi}{4} \right)\), which are both \(\frac{\sqrt{2}}{2}\), to find the rectangular form of the complex number.
Interpret the complex number \(\frac{\sqrt{2}}{2} + i \frac{\sqrt{2}}{2}\) as a point in the complex plane with coordinates \((\frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2})\).
Plot this point on the complex plane, where the x-axis represents the real part and the y-axis represents the imaginary part, to visualize \(e^{\frac{\pi i}{4}}\).

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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 for any real number θ, e^(iθ) = cos θ + i sin θ. This fundamental relationship connects complex exponentials with trigonometric functions, allowing complex numbers to be represented in polar form.
추천 영상:
6:36
Quadratic Formula

Complex Numbers in Polar Form

A complex number can be expressed as r(cos θ + i sin θ), where r is the magnitude and θ is the argument (angle). Using Euler's formula, this is written as re^(iθ), which simplifies plotting and multiplication of complex numbers.
추천 영상:
04:47
Complex Numbers In Polar Form

Plotting Complex Numbers on the Complex Plane

Complex numbers are plotted on a plane with the real part on the x-axis and the imaginary part on the y-axis. The angle θ from the positive real axis and the magnitude r determine the point's position, making polar form useful for visualization.
추천 영상:
03:47
How To Plot Complex Numbers