Math Problem Statement

To find 𝑓 ( 1 / 2 ) f(1/2) using synthetic division and the Remainder Theorem, we will first perform synthetic division of the polynomial 𝑓 ( π‘₯ )

2 π‘₯ 5 + 5 π‘₯ 4 βˆ’ 4 π‘₯ 2 + 3 π‘₯ βˆ’ 1 f(x)=2x 5 +5x 4 βˆ’4x 2 +3xβˆ’1 by π‘₯ βˆ’ 1 2 xβˆ’ 2 1 ​ .

Step 1: Set up synthetic division.

We will use 1 2 2 1 ​ and the coefficients of 𝑓 ( π‘₯ ) f(x):

Solution

To use synthetic division to evaluate f(12)f\left(\frac{1}{2}\right) with the Remainder Theorem, we’ll set up synthetic division as follows:

Step 1: Set up for synthetic division

  1. Identify the polynomial: The polynomial is f(x)=2x5+5x4βˆ’4x2+3xβˆ’1f(x) = 2x^5 + 5x^4 - 4x^2 + 3x - 1
  2. Fill in missing terms: Since there is no x3x^3 term, we’ll use a coefficient of 00 for that term.
    • Coefficients are: 2,5,0,βˆ’4,3,βˆ’12, 5, 0, -4, 3, -1
  3. Set up the synthetic division: We'll divide by xβˆ’12x - \frac{1}{2}, meaning we use 12\frac{1}{2} in synthetic division.

Step 2: Perform synthetic division

Set up synthetic division as follows:

  • Write down the coefficients: 2,5,0,βˆ’4,3,βˆ’12, 5, 0, -4, 3, -1
  • Use 12\frac{1}{2} to divide.

The process goes as follows:

  1. Bring down the first coefficient, 22.
  2. Multiply 22 by 12\frac{1}{2} to get 11, then add to the next coefficient 55, resulting in 66.
  3. Multiply 66 by 12\frac{1}{2} to get 33, then add to 00, resulting in 33.
  4. Multiply 33 by 12\frac{1}{2} to get 1.51.5, then add to βˆ’4-4, resulting in βˆ’2.5-2.5.
  5. Multiply βˆ’2.5-2.5 by 12\frac{1}{2} to get βˆ’1.25-1.25, then add to 33, resulting in 1.751.75.
  6. Multiply 1.751.75 by 12\frac{1}{2} to get 0.8750.875, then add to βˆ’1-1, resulting in βˆ’0.125-0.125.

The last value, βˆ’0.125-0.125, is the remainder. According to the Remainder Theorem, this is also the value of f(12)f\left(\frac{1}{2}\right).

Answer

f(12)=βˆ’0.125f\left(\frac{1}{2}\right) = -0.125

Would you like more detailed steps or additional explanation?


  1. What is synthetic division, and how is it used with polynomials?
  2. How does the Remainder Theorem simplify evaluating polynomials?
  3. Why is a missing term represented with a coefficient of zero in synthetic division?
  4. Can synthetic division be used for divisors other than linear factors?
  5. What are other methods to find f(12)f\left(\frac{1}{2}\right) besides synthetic division?

Tip: Remember, the Remainder Theorem provides a quick way to evaluate polynomials without fully expanding powers or substituting directly.

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Math Problem Analysis

Mathematical Concepts

Synthetic Division
Remainder Theorem
Polynomial Evaluation

Formulas

Synthetic Division Process
f(c) = Remainder when f(x) is divided by x - c (Remainder Theorem)

Theorems

Remainder Theorem

Suitable Grade Level

Grades 10-12