In Exercises 1–4, use the vertex and intercepts to sketch the graph of each quadratic function. Give the equation for the parabola's axis of symmetry. Use the graph to determine the function's domain and range.
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
4. Polynomial Functions
Quadratic Functions
Problem 5
Textbook Question
Fill in the blank(s) to correctly complete each sentence. The vertex of the graph of ƒ(x) = x2 + 2x + 4 has x-coordinate ____ .
Verified step by step guidance1
Identify the quadratic function given: \(f(x) = x^2 + 2x + 4\).
Recall that the vertex of a parabola given by \(f(x) = ax^2 + bx + c\) has an x-coordinate found by the formula \(x = -\frac{b}{2a}\).
In this function, \(a = 1\) and \(b = 2\), so substitute these values into the formula: \(x = -\frac{2}{2 \times 1}\).
Simplify the expression to find the x-coordinate of the vertex: \(x = -\frac{2}{2}\).
Conclude that the x-coordinate of the vertex is the simplified value from the previous step.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Quadratic Functions and Their Graphs
A quadratic function is a polynomial of degree two, typically written as f(x) = ax^2 + bx + c. Its graph is a parabola that opens upward if a > 0 and downward if a < 0. Understanding the shape and properties of parabolas is essential for analyzing their vertices.
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Vertex of a Parabola
The vertex of a parabola is the point where the graph changes direction, representing either a maximum or minimum value. For a quadratic function f(x) = ax^2 + bx + c, the vertex's x-coordinate can be found using the formula x = -b/(2a). This helps locate the exact position of the vertex on the x-axis.
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Using the Vertex Formula
The vertex formula x = -b/(2a) is derived from completing the square or using calculus. It provides a quick way to find the x-coordinate of the vertex without graphing. Applying this formula to f(x) = x^2 + 2x + 4, where a=1 and b=2, yields the vertex's x-coordinate.
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