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Graphical Analysis, (a) use the zero or root feature of a graphing utility to approximate the zeros of the function accurate to three decimal places, (b) determine the exact value of one of the zeros (use synthetic division to verify your result), and (c) factor the polynomial completely. $$f(x)=x^{4}-3 x^{2}+2$$

Short Answer

Expert verified
The approximate zeros of the function are \(x = 1\), \(-1\), and \(x = \sqrt{2}\), \(-\sqrt{2}\). One exact zero is \(x=1\). By performing synthetic division, we can confirm \(x = 1\) to be a zero of the function. Finally, the polynomial can be completely factorized as \(x^4 - 3x^2 + 2 = (x^2 - 1)^2 - 1 = (x^2 - \sqrt{2})(x^2 + \sqrt{2})\).

Step by step solution

01

Approximate the Zeros Using a Graphing Utility

To find the zeros of the polynomial \(f(x)=x^{4}-3x^{2}+2\), use a graphing utility. Plot the function \(f(x)=x^{4}-3x^{2}+2\) and determine where it crosses the x-axis, which represents the function's zeros. This step will provide an approximation of the roots of the equation.
02

Determine the Exact Value of a Zero

Next, select one of the zeros observed on the graph and determine its exact value. This can be done more accurately by setting \(f(x)\) equal to zero and solving for \(x\) manually. For example, if the graphing utility suggested \(x = 1\) as a zero, you'd solve the equation \(1^4 - 3(1)^2 + 2 = 0\) in order to confirm.
03

Verify the Zero Using Synthetic Division

Next step is to confirm that \(x = 1\) is indeed a zero of the polynomial by using synthetic division. This involves dividing \(x^4 - 3x^2 + 2\) by \(x - 1\). If the remainder is zero after performing the synthetic division, then \(x = 1\) is indeed a zero of the polynomial.
04

Factor the Polynomial Completely

The final step is to factor the polynomial completely. Since you know \(x=1\) is a zero of the polynomial, it means \((x-1)\) is a factor of the polynomial. Perform polynomial division to get the other factor, or use the Factor theorem to factorize the function.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Zeros of polynomials
In algebra, one of the key goals is to decipher the zeros or roots of polynomials. These zeros are the values of \(x\) where the polynomial evaluates to zero. For instance, if you have a polynomial function \(f(x) = x^4 - 3x^2 + 2\), the zeros are the values of \(x\) that make the equation \(f(x) = 0\). Finding these zeros is crucial, as they reveal the points where the graph of the polynomial intersects the x-axis. Moreover, determining the zeros can help in factoring the polynomial into simpler expressions.

Zeros can be real or complex numbers. Real zeros can be straightforward to spot as they are the points where the graph touches or crosses the x-axis. Tools like graphing utilities make finding real zeros easier by providing a visual representation of these intersections.
Synthetic division
Synthetic division is a streamlined method of dividing polynomials that uses less written work compared to traditional long division. It is especially useful when dividing by a linear term of the form \(x - c\). For our function \(f(x) = x^4 - 3x^2 + 2\), if you have identified a potential zero, say \(x = 1\), synthetic division helps verify it.

Here's how synthetic division works:
  • Write the coefficients of the polynomial. For \(f(x) = x^4 - 3x^2 + 2\), you need to include zero terms for any missing degrees: 1, 0, -3, 0, 2.
  • Use the zero you want to test (in this case, 1) in the synthetic division process.
  • The essential part: bring down the leading coefficient, multiply with the test zero and continue through the coefficients, adding each result to the next coefficient.
  • If at the end the remainder is zero, it means \(x = 1\) is a zero of the polynomial.
By confirming zeros effectively, synthetic division assists in simplifying the polynomial equation without excessive computation.
Factor theorem
The Factor theorem is a continuation of polynomial division principles. It is a powerful tool that connects the concept of zeros with factors of a polynomial. Essentially, it states that if \(c\) is a root of the polynomial \(f(x)\), then \((x - c)\) is a factor of \(f(x)\). Conversely, if \(f(c) = 0\), then \(x = c\) is a zero of the polynomial.

In practical application, if you have confirmed that \(x = 1\) is a zero of \(f(x) = x^4 - 3x^2 + 2\), then \((x - 1)\) should divide the polynomial evenly. Utilizing synthetic division or polynomial division can illustrate this: once divided, the quotient left is another polynomial which may be further factored. Each zero found is vital in breaking down the polynomial fully into its simplest factors. This insight into the relationship between zeros and factors of a polynomial is invaluable for graphing, integration, and solving polynomial equations more efficiently. It taps into the structure of polynomials, allowing you to see beyond just equations into their foundational components.

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