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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 33

In Exercises 13–34, test for symmetry and then graph each polar equation. r cos θ = −3

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1
Rewrite the given polar equation \(r \cos \theta = -3\) in a more recognizable form. Recall that \(r \cos \theta\) represents the \(x\)-coordinate in Cartesian coordinates, so the equation can be rewritten as \(x = -3\).
Analyze the symmetry of the equation with respect to the polar axes: the polar axis (the positive \(x\)-axis), the line \(\theta = \frac{\pi}{2}\) (the vertical axis), and the pole (origin).
Test for symmetry about the polar axis by replacing \(\theta\) with \(-\theta\) in the original equation and checking if the equation remains unchanged.
Test for symmetry about the line \(\theta = \frac{\pi}{2}\) by replacing \(\theta\) with \(\pi - \theta\) and checking if the equation remains unchanged.
Test for symmetry about the pole by replacing \(r\) with \(-r\) and \(\theta\) with \(\theta + \pi\) and checking if the equation remains unchanged. Then, sketch the graph of the line \(x = -3\) in the Cartesian plane, which corresponds to a vertical line 3 units to the left of the origin.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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주요 개념

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

Polar Coordinates and Equations

Polar coordinates represent points using a radius r and an angle θ from the positive x-axis. Polar equations express relationships between r and θ, describing curves in the plane. Understanding how to interpret and manipulate these equations is essential for graphing and analyzing their properties.
추천 영상:
05:32
Intro to Polar Coordinates

Symmetry Tests in Polar Graphs

Symmetry in polar graphs can be tested about the polar axis, the line θ = π/2, and the pole (origin). These tests involve substituting θ with -θ, π - θ, or replacing r with -r to check if the equation remains unchanged. Identifying symmetry helps simplify graphing and understanding the curve's shape.
추천 영상:
3:19
Cardioids

Conversion Between Polar and Cartesian Coordinates

Converting polar equations to Cartesian form using x = r cos θ and y = r sin θ can simplify analysis. For example, r cos θ = x, so the given equation can be rewritten in Cartesian coordinates to identify the curve type. This conversion aids in graphing and understanding the geometric nature of the equation.
추천 영상:
05:32
Intro to Polar Coordinates