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
Dividing Polynomials
Problem 39
Textbook Question
In Exercises 33–40, use synthetic division and the Remainder Theorem to find the indicated function value. f(x)=2x^4−5x^3−x^2+3x+2;f(− 1/2)
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Identify the polynomial function \( f(x) = 2x^4 - 5x^3 - x^2 + 3x + 2 \) and the value \( x = -\frac{1}{2} \) for which we need to find \( f(-\frac{1}{2}) \).
Set up synthetic division using \( -\frac{1}{2} \) as the divisor. Write down the coefficients of the polynomial: \( 2, -5, -1, 3, 2 \).
Bring down the leading coefficient (2) to the bottom row.
Multiply the divisor \( -\frac{1}{2} \) by the number just written on the bottom row (2) and write the result under the next coefficient (-5).
Add the numbers in the second column: \(-5 + (-1) = -6\). Repeat the multiplication and addition process for the remaining coefficients. The final number in the bottom row is the remainder, which is \( f(-\frac{1}{2}) \).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Synthetic Division
Synthetic division is a simplified method for dividing a polynomial by a linear binomial of the form (x - c). It involves using the coefficients of the polynomial and performing a series of multiplications and additions, which allows for quicker calculations compared to long division. This technique is particularly useful for evaluating polynomials at specific values, as it can directly yield the remainder, which corresponds to the function value at that point.
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Remainder Theorem
The Remainder Theorem states that when a polynomial f(x) is divided by a linear divisor (x - c), the remainder of this division is equal to f(c). This theorem provides a quick way to evaluate the polynomial at a specific point without fully performing the division. In the context of the given problem, using the Remainder Theorem allows us to find f(-1/2) efficiently by applying synthetic division.
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Polynomial Functions
A polynomial function is a mathematical expression involving a sum of powers in one or more variables multiplied by coefficients. The general form of a polynomial in one variable x is f(x) = a_nx^n + a_(n-1)x^(n-1) + ... + a_1x + a_0, where a_n are constants and n is a non-negative integer. Understanding the structure of polynomial functions is essential for applying synthetic division and the Remainder Theorem effectively, as it helps in recognizing the degree and behavior of the function.
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