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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 67

In Exercises 64–70, graph each polar equation. Be sure to test for symmetry.r = 2 + cos θ

검증된 단계별 안내
1
Identify the type of polar equation: The given equation \( r = 2 + \cos \theta \) is a limaçon, which is a type of polar curve.
Test for symmetry: Check for symmetry with respect to the polar axis (x-axis), the line \( \theta = \frac{\pi}{2} \) (y-axis), and the pole (origin). For this equation, substitute \( \theta \) with \( -\theta \) to test for x-axis symmetry, and substitute \( r \) with \(-r\) to test for origin symmetry.
Determine key points: Calculate \( r \) for key angles such as \( \theta = 0, \frac{\pi}{2}, \pi, \frac{3\pi}{2} \) to find specific points on the graph.
Plot the points: Use the calculated points to plot the graph on polar coordinates. Remember that the graph will be symmetric based on the tests conducted earlier.
Sketch the curve: Connect the plotted points smoothly to form the limaçon shape, ensuring to reflect any symmetries identified in the earlier steps.

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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

Polar coordinates represent points in a plane using a distance from a reference point (the pole) and an angle from a reference direction. In the equation r = 2 + cos θ, 'r' denotes the radius or distance from the origin, while 'θ' is the angle measured from the positive x-axis. Understanding how to convert between polar and Cartesian coordinates is essential for graphing polar equations.
추천 영상:
05:32
Intro to Polar Coordinates

Symmetry in Polar Graphs

Symmetry in polar graphs can be determined by analyzing the equation with respect to specific angles. A polar graph is symmetric about the polar axis if replacing θ with -θ yields the same equation, and it is symmetric about the line θ = π/2 if replacing θ with π - θ does so. Testing for symmetry helps in sketching the graph accurately and understanding its properties.
추천 영상:
3:19
Cardioids

Graphing Polar Equations

Graphing polar equations involves plotting points based on the values of 'r' for various angles 'θ'. The equation r = 2 + cos θ describes a limaçon shape, which can exhibit different characteristics based on the coefficients involved. To graph it effectively, one must calculate 'r' for key angles (like 0, π/2, π, and 3π/2) and then plot these points in the polar coordinate system.
추천 영상:
3:47
Introduction to Common Polar Equations