Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
3. Functions
Intro to Functions & Their Graphs
Problem 108
Textbook Question
In Exercises 107–108, write the standard form of the equation of the circle with the given center and radius. Center (-2. 4), r = 6
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1
Identify the standard form of the equation of a circle, which is \((x - h)^2 + (y - k)^2 = r^2\), where \((h, k)\) is the center and \(r\) is the radius.
Substitute the given center \((-2, 4)\) into the equation, replacing \(h\) with \(-2\) and \(k\) with \(4\).
Substitute the given radius \(r = 6\) into the equation.
Write the equation as \((x - (-2))^2 + (y - 4)^2 = 6^2\).
Simplify the equation to \((x + 2)^2 + (y - 4)^2 = 36\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Standard Form of a Circle's Equation
The standard form of a circle's equation is given by (x - h)² + (y - k)² = r², where (h, k) is the center of the circle and r is the radius. This format allows for easy identification of the circle's center and radius, facilitating graphing and analysis.
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Coordinates of the Center
The center of a circle is represented by the coordinates (h, k). In this case, the center is (-2, 4), meaning the circle is positioned 2 units left and 4 units up from the origin on the Cartesian plane. Understanding the center's coordinates is crucial for accurately writing the equation.
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Radius of a Circle
The radius of a circle is the distance from the center to any point on the circle. In this problem, the radius is given as r = 6, which means that every point on the circle is 6 units away from the center. This value is essential for determining the right side of the standard form equation.
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