Identify the conic represented by the equation without completing the square. y^2 + 4x + 2y - 15 = 0
Table of contents
- 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
8. Conic Sections
Parabolas
Problem 37
Textbook Question
Find the vertex, focus, and directrix of the parabola with the given equation. Then graph the parabola. y^2 = 8x
Verified step by step guidance1
Rewrite the given equation y^2 = 8x in standard form for a parabola. The standard form for a parabola that opens horizontally is (y - k)^2 = 4p(x - h), where (h, k) is the vertex and p is the distance from the vertex to the focus or directrix.
Compare the given equation y^2 = 8x with the standard form. Notice that h = 0, k = 0, and 4p = 8. Solve for p by dividing 8 by 4, which gives p = 2.
Identify the vertex of the parabola. Since h = 0 and k = 0, the vertex is at (0, 0).
Determine the focus of the parabola. Since the parabola opens to the right (positive x-direction) and p = 2, the focus is located at (h + p, k), which is (0 + 2, 0) or (2, 0).
Find the directrix of the parabola. The directrix is a vertical line located at x = h - p. Substituting h = 0 and p = 2, the directrix is x = -2.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Parabola Definition
A parabola is a symmetric curve formed by the intersection of a cone with a plane parallel to its side. In algebra, it can be represented by quadratic equations, typically in the form y^2 = 4px or x = 4py, where p is the distance from the vertex to the focus. Understanding the standard form of a parabola is essential for identifying its key features.
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Vertex, Focus, and Directrix
The vertex of a parabola is the point where it changes direction, while the focus is a fixed point inside the parabola that determines its shape. The directrix is a line perpendicular to the axis of symmetry of the parabola, equidistant from the vertex as the focus. These elements are crucial for graphing the parabola and understanding its geometric properties.
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Vertex Form
Graphing Parabolas
Graphing a parabola involves plotting its vertex, focus, and directrix, and understanding its orientation (opening direction). For the equation y^2 = 8x, the parabola opens to the right, and knowing how to derive and plot these key points allows for an accurate representation of the curve. Familiarity with transformations and symmetry also aids in graphing.
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