Convert the point to polar coordinates.
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
9. Polar Equations
Convert Points Between Polar and Rectangular Coordinates
Problem 19c
Textbook Question
For each pair of polar coordinates, (c) give the rectangular coordinates for the point. See Examples 1 and 2(a).
(―3 , ―210°)
Verified step by step guidance1
Recall the relationship between polar coordinates \((r, \theta)\) and rectangular coordinates \((x, y)\), which is given by the formulas: \(x = r \cos(\theta)\) and \(y = r \sin(\theta)\).
Identify the given polar coordinates: \(r = -3\) and \(\theta = -210^\circ\).
Convert the angle \(\theta\) to a standard position if needed. Since \(-210^\circ\) is negative, you can add \(360^\circ\) to find a positive coterminal angle: \(-210^\circ + 360^\circ = 150^\circ\).
Calculate the rectangular coordinates using the formulas: \(x = -3 \cos(150^\circ)\) and \(y = -3 \sin(150^\circ)\).
Evaluate the cosine and sine values for \(150^\circ\) and multiply by \(-3\) to find the exact rectangular coordinates \((x, y)\).
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
2mPlay a video:
0 Comments
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 can be positive or negative, and θ is usually given in degrees or radians.
Recommended video:
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 translates the point from a radius-angle format to Cartesian coordinates on the xy-plane.
Recommended video:
Convert Points from Polar to Rectangular
Handling Negative Radius and Angle Measures
A negative radius means the point lies in the direction opposite to the angle θ, effectively adding 180° to θ. Negative angles indicate rotation clockwise from the positive x-axis. Properly adjusting these values ensures accurate conversion to rectangular coordinates.
Recommended video:
Example 2
Related Videos
Related Practice
Multiple Choice
332
views
