Give the center and radius of the circle represented by each equation. x2+y2+6x+8y+9=0
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- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
3. Functions
Intro to Functions & Their Graphs
Problem 35
Textbook Question
Describe the graph of each equation as a circle, a point, or nonexistent. If it is a circle, give the center and radius. If it is a point, give the coordinates. x2+y2+2x-6y+14=0
Verified step by step guidance1
Start by rewriting the given equation: \(x^2 + y^2 + 2x - 6y + 14 = 0\).
Group the \(x\) terms and \(y\) terms together: \((x^2 + 2x) + (y^2 - 6y) + 14 = 0\).
Complete the square for the \(x\) terms: take half of 2, which is 1, and square it to get 1. Add and subtract 1 inside the equation.
Complete the square for the \(y\) terms: take half of -6, which is -3, and square it to get 9. Add and subtract 9 inside the equation.
Rewrite the equation as \((x^2 + 2x + 1) - 1 + (y^2 - 6y + 9) - 9 + 14 = 0\), then simplify and express it in the form \((x + 1)^2 + (y - 3)^2 = r^2\) to identify the center and radius.
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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 Equation
The standard form of a circle's equation is (x - h)^2 + (y - k)^2 = r^2, where (h, k) is the center and r is the radius. Converting a general quadratic equation into this form helps identify the circle's properties.
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Circles in Standard Form
Completing the Square
Completing the square is a method used to rewrite quadratic expressions in a perfect square form. This technique is essential to transform the given equation into the standard circle form by grouping x and y terms separately.
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Solving Quadratic Equations by Completing the Square
Determining the Nature of the Graph
After rewriting the equation, the radius squared (r^2) determines the graph's nature: if r^2 > 0, it's a circle; if r^2 = 0, it's a point; if r^2 < 0, the graph does not exist in the real plane.
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