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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 43

In Exercises 41–48, the rectangular coordinates of a point are given. Find polar coordinates of each point. Express θ in radians. _ (2,−2√3)

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Recall that to convert rectangular coordinates \((x, y)\) to polar coordinates \((r, \theta)\), we use the formulas: \(r = \sqrt{x^2 + y^2}\) and \(\theta = \tan^{-1}\left(\frac{y}{x}\right)\).
Calculate the radius \(r\) by substituting \(x = 2\) and \(y = -2\sqrt{3}\) into the formula: \(r = \sqrt{(2)^2 + (-2\sqrt{3})^2}\).
Simplify the expression under the square root to find the exact value of \(r\).
Find the angle \(\theta\) by calculating \(\theta = \tan^{-1}\left(\frac{-2\sqrt{3}}{2}\right)\), which simplifies to \(\tan^{-1}(-\sqrt{3})\).
Determine the correct quadrant for \(\theta\) based on the signs of \(x\) and \(y\) (here, \(x > 0\) and \(y < 0\)), and adjust \(\theta\) accordingly to express it in radians.

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주요 개념

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

Rectangular and Polar Coordinate Systems

Rectangular coordinates (x, y) represent a point's position using horizontal and vertical distances from the origin. Polar coordinates (r, θ) describe the same point by its distance r from the origin and the angle θ formed with the positive x-axis, measured in radians.
추천 영상:
05:32
Intro to Polar Coordinates

Conversion Formulas Between Coordinates

To convert from rectangular to polar coordinates, use r = √(x² + y²) to find the radius and θ = arctan(y/x) to find the angle. Adjust θ based on the quadrant of the point to ensure the angle correctly represents the point's direction.
추천 영상:
05:32
Intro to Polar Coordinates

Angle Measurement in Radians and Quadrant Considerations

Angles in polar coordinates are measured in radians, where 2π radians equal 360°. Since arctan(y/x) returns values between -π/2 and π/2, you must consider the signs of x and y to determine the correct quadrant and adjust θ accordingly for an accurate angle.
추천 영상:
5:04
Converting between Degrees & Radians