Chapter 5: Problem 36
For the following exercises, use synthetic division to find the quotient. $$ \left(4 x^{4}-2 x^{3}-4 x+2\right) \div(2 x-1) $$
Short Answer
Expert verified
The quotient is \(4x^3 - 4\) with a remainder of 0.
Step by step solution
01
Set Up the Synthetic Division
To perform synthetic division, identify the root of the divisor \((2x-1)\), which is \(x = \frac{1}{2}\). Write down the coefficients of the dividend \(4x^4 - 2x^3 + 0x^2 - 4x + 2\). Note that we include a 0 for the missing \(x^2\) term. The coefficients are \([4, -2, 0, -4, 2]\).
02
Bring Down the Leading Coefficient
Start the synthetic division by bringing down the leading coefficient, which is 4, to the bottom row.
03
Multiply and Add
Multiply the root \(\frac{1}{2}\) by the leading coefficient 4 and place it under the next coefficient (-2). Add -2 and 2 to get 0. Continue the process by multiplying \(\frac{1}{2}\) by the result (0) and add to the next coefficient (0). Repeat this for all coefficients. You should have:- Multiply \(\frac{1}{2}\) by 4, add to -2, to get 0.- Multiply \(\frac{1}{2}\) by 0, add to 0, to get 0.- Multiply \(\frac{1}{2}\) by 0, add to -4, to get -4.- Multiply \(\frac{1}{2}\) by -4, add to 2, to get 0.
04
Interpret the Result
The numbers in the bottom row represent the coefficients of the quotient polynomial: \(4x^3 + 0x^2 + 0x - 4\). The last number (0) is the remainder.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Polynomials
Polynomials are mathematical expressions consisting of variables and coefficients, structured in a way that they include terms of the form \( ax^n \).These terms are combined using addition, subtraction, and multiplication operators.Here are some key points to understand polynomials:
- The variable \( x \) can have non-negative integer exponents.
- A polynomial is usually expressed in a standard form, ordered from the highest power of \( x \) to the lowest.
- Each term in a polynomial contains a coefficient, which is a real number.
- The highest exponent of the variable in the polynomial indicates its degree. For example, a degree four polynomial will have the highest term as \( x^4 \).
Roots of Polynomials
The roots of a polynomial are the solutions where the polynomial equals zero.Finding roots is essential in simplifying and solving polynomial equations.Here are some important aspects about polynomial roots:
- For a polynomial equation \( P(x) = 0 \), the roots are the values of \( x \) that make the equation true.
- The Fundamental Theorem of Algebra states that a polynomial of degree \( n \) will have exactly \( n \) roots, which may be real or complex, some of which might be repeated.
- In synthetic division, verifying roots is essential as the method is used to divide polynomials by linear factors \((x - r)\), where \( r \) is a root of the polynomial.
Synthetic Division Steps
Synthetic division is a handy method for dividing polynomials when the divisor is in the linear form \((x - r)\).The approach simplifies long division by focusing on coefficients.Here's how to perform synthetic division:
- First, determine the root \( r \) from the divisor, such as \((2x-1)\), which leads to \( r = \frac{1}{2} \).
- Next, list the coefficients of the polynomial in descending order of power. Don’t forget to include 0 for any missing terms.
- Place the root \( \frac{1}{2} \) to the left of the setup. Bring down the first coefficient directly to the bottom row.
- Multiply this coefficient by the root \( r \) and carry the result to the line of coefficients, then add it to the next coefficient.
- Continue the process: multiply the new number in the bottom row by \( r \) and add it to the next coefficient above, repeating till the end.
- The resulting numbers at the bottom row are the coefficients of the quotient and any remainder.