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
4. Polynomial Functions
Understanding Polynomial Functions
Problem 22a
Textbook Question
Use an end behavior diagram, , , , or , to describe the end behavior of the graph of each polynomial function. See Example 2. ƒ(x)=-x^3-4x^2+2x-1
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1
Identify the leading term of the polynomial function, which is the term with the highest power of x. In this case, the leading term is \(-x^3\).
Determine the degree of the polynomial. The degree is the highest power of x, which is 3 in this case, indicating that the polynomial is a cubic function.
Examine the leading coefficient, which is the coefficient of the leading term. Here, the leading coefficient is \(-1\).
Use the degree and the leading coefficient to determine the end behavior of the polynomial. Since the degree is odd and the leading coefficient is negative, the end behavior is such that as \(x \to -\infty\), \(f(x) \to \infty\) and as \(x \to \infty\), \(f(x) \to -\infty\).
Sketch an end behavior diagram to visually represent the behavior of the graph as \(x\) approaches positive and negative infinity, showing the graph rising to the left and falling to the right.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
End Behavior of Polynomials
The end behavior of a polynomial function describes how the function behaves as the input values (x) approach positive or negative infinity. This behavior is primarily determined by the leading term of the polynomial, which is the term with the highest degree. For example, in the polynomial f(x) = -x^3 - 4x^2 + 2x - 1, the leading term is -x^3, indicating that as x approaches infinity, f(x) will approach negative infinity, and as x approaches negative infinity, f(x) will also approach positive infinity.
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Leading Coefficient Test
The leading coefficient test helps predict the end behavior of a polynomial function based on the sign and degree of the leading term. If the leading coefficient is positive and the degree is even, the ends of the graph will rise in both directions. Conversely, if the leading coefficient is negative and the degree is odd, like in the case of f(x) = -x^3, the graph will fall to the right and rise to the left, shaping the overall behavior of the polynomial.
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Graphing Polynomial Functions
Graphing polynomial functions involves plotting points based on the function's values and understanding its shape, which is influenced by its degree and leading coefficient. The graph can exhibit various features such as intercepts, turning points, and asymptotic behavior. For the polynomial f(x) = -x^3 - 4x^2 + 2x - 1, recognizing its end behavior and critical points will aid in sketching an accurate representation of the function.
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