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Ch. 8 - Complex Numbers, Polar Equations, and Parametric Equations
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161Not the one you use?Change textbook
Chapter 9, Problem 13c

For each pair of polar coordinates, (c) give the rectangular coordinates for the point. See Examples 1 and 2(a).


(1 , 45°)

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1
Recall the relationship between polar coordinates \((r, \theta)\) and rectangular coordinates \((x, y)\), where \(x = r \cos(\theta)\) and \(y = r \sin(\theta)\).
Identify the given polar coordinates: \(r = 1\) and \(\theta = 45^\circ\).
Convert the angle \(\theta\) from degrees to radians if necessary, but since \(45^\circ\) is a common angle, you can use the exact trigonometric values directly.
Calculate the \(x\)-coordinate using \(x = 1 \times \cos(45^\circ)\).
Calculate the \(y\)-coordinate using \(y = 1 \times \sin(45^\circ)\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Polar Coordinates

Polar coordinates represent a point in the plane using a distance from the origin (radius r) and an angle θ measured from the positive x-axis. The pair (r, θ) specifies the location uniquely, where r ≥ 0 and θ is typically in degrees or radians.
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Intro to Polar Coordinates

Conversion from Polar to Rectangular Coordinates

To convert polar coordinates (r, θ) to rectangular coordinates (x, y), use the formulas x = r cos θ and y = r sin θ. This transformation maps the point from a radial system to the Cartesian plane, facilitating easier computation and visualization.
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Convert Points from Polar to Rectangular

Trigonometric Functions and Angle Measurement

Understanding sine and cosine functions is essential for conversion, as they relate angles to ratios of sides in right triangles. Angles must be correctly interpreted in degrees or radians to apply these functions accurately during coordinate conversion.
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Introduction to Trigonometric Functions