/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 42 Use the remainder theorem to eva... [FREE SOLUTION] | 91Ó°ÊÓ

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Use the remainder theorem to evaluate \(P(x)\) as given. \(P(x)=-2 x^{3}+9 x^{2}-11\) a. \(P(-2)\) b. \(P(-1)\)

Short Answer

Expert verified
P(-2) = 41; P(-1) = 0.

Step by step solution

01

Understanding the Remainder Theorem

The Remainder Theorem states that for a polynomial \(P(x)\), the remainder of the division of \(P(x)\) by \(x-a\) is \(P(a)\). Hence, to find \(P(a)\), we don't need to perform long division. We can directly substitute \(a\) into the polynomial \(P(x)\).
02

Evaluate P(-2)

To find \(P(-2)\), substitute \(-2\) into the polynomial: \[P(-2) = -2(-2)^{3} + 9(-2)^{2} - 11\] Calculate step by step: - \((-2)^3 = -8\) - \(-2 \times -8 = 16\) - \((-2)^2 = 4\)- \(9 \times 4 = 36\) - Combine the results: \(16 + 36 - 11 = 41\). So, \(P(-2) = 41\).
03

Evaluate P(-1)

To find \(P(-1)\), substitute \(-1\) into the polynomial: \[P(-1) = -2(-1)^{3} + 9(-1)^{2} - 11\] Calculate step by step:- \((-1)^3 = -1\) - \(-2 \times -1 = 2\) - \((-1)^2 = 1\) - \(9 \times 1 = 9\)- Combine the results: \(2 + 9 - 11 = 0\). So, \(P(-1) = 0\).

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Key Concepts

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

Polynomial Evaluation
Polynomial evaluation is the process of finding the value of a polynomial function at a given point. This involves substituting a specific value for the variable, usually denoted as \( x \), in the polynomial equation and then performing arithmetic operations to simplify it. This process helps to understand the behavior of the polynomial at specific values and is essential in various areas of mathematics and applied sciences. In general, given a polynomial \( P(x) \) and a specific value \( a \), evaluation involves replacing \( x \) with \( a \) and simplifying:
  • If \( P(x) = ax^n + bx^{n-1} + ... + z \).
  • Substitute \( x = a \) to find \( P(a) \).
This substitution allows you to find the function's value without modifying the polynomial's overall structure. It helps not only in academic exercises but also in real-world applications like physics, economics, and computer science.
Substitution Method
The substitution method is a simple yet powerful technique used in algebra to solve equations or evaluate expressions. When evaluating polynomials, the substitution method can help determine the polynomial's value at a certain point. It involves replacing the variable in the polynomial with a specific number and then performing the necessary arithmetic operations. For example, to evaluate the polynomial \( P(x) = -2x^3 + 9x^2 - 11 \) at \( x = -2 \), follow these steps:
  • Substitute \( -2 \) for \( x \).
  • Compute each term separately: \((-2)^3 = -8\), multiplied by \(-2\) gives \(16\); \((-2)^2 = 4\), multiplied by \(9\) gives \(36\).
  • Finally, combine all results to get the total value by addition and subtraction: \(16 + 36 - 11 = 41\).
This straightforward approach is efficient, especially for higher-degree polynomials, as it avoids complex calculations involved in polynomial division.
Polynomial Division
Polynomial division is a method used to divide one polynomial by another. It is similar to long division with numbers and is typically used when you want to divide a polynomial evenly. However, thanks to the Remainder Theorem, in many cases, a full polynomial division isn't necessary just to find the value of the polynomial at a specific point. The process involves dividing the terms of the polynomial individually, starting with the highest degree term. This step-by-step approach continues until all terms are divided. Polynomial division helps in understanding polynomial structures and functions more profoundly, especially when trying to simplify complex polynomial expressions or solve algebraic expressions.
Remainder Calculation
Remainder calculation in polynomials refers to the numerical value remaining after the division of one polynomial by another. This concept is widely used in conjunction with the Remainder Theorem, which states that the remainder of a polynomial \( P(x) \) after division by \( x-a \) is simply \( P(a) \).This means instead of going through the entire division process, you can quickly find the remainder (and thus evaluate the polynomial at a point) by substitution:
  • Take the polynomial \( P(x) \).
  • Substitute \( a \) into the polynomial to find \( P(a) \).
This substitution effectively gives you the remainder directly, making the remainder calculation both swift and efficient. By avoiding full division, it simplifies finding values of polynomials, particularly for large or complex expressions.

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Most popular questions from this chapter

The volume of water in a rectangular, in-ground, swimming pool is given by \(V(x)=x^{3}+11 x^{2}+24 x,\) where \(v(x)\) is the volume in cubic feet when the water is \(x\) ft high. (a) Use the remainder theorem to find the volume when \(x=3 \mathrm{ft}\). (b) If the volume is \(100 \mathrm{ft}^{3}\) of water, what is the height \(x ?\) (c) If the maximum capacity of the pool is \(1000 \mathrm{ft}^{3},\) what is the maximum depth (to the nearest integer)?

Graph each function using the Guidelines for Graphing Rational Functions, which is simply modified to include nonlinear asymptotes. Clearly label all intercepts and asymptotes and any additional points used to sketch the graph. $$Y_{1}=\frac{x^{3}-3 x+2}{x^{2}-9}$$

Discuss/Explain each of the following: (a) irreducible quadratic factors, (b) factors that are complex conjugates, (c) zeroes of multiplicity \(m\), and (d) upper bounds on the zeroes of a polynomial.

Maximum profit: An automobile manufacturer can produce up to 300 cars per day. The profit made from the sale of these vehicles can be modeled by the function \(P(x)=-10 x^{2}+3500 x-66,000\) where \(P(x)\) is the profit in dollars and \(x\) is the number of automobiles made and sold. Based on this model: a. Find the \(y\) -intercept and explain what it means in this context. b. Find the \(x\) -intercepts and explain what they mean in this context. c. How many cars should be made and sold to maximize profit? d. What is the maximum profit?

The surface area of a spherical cap is given by \(S=2 \pi r h,\) where \(r\) is the radius of the sphere and \(h\) is the perpendicular distance from the sphere's surface to the plane intersecting the sphere, forming the cap. The volume of the cap is \(V=\frac{1}{3} \pi h^{2}(3 r-h) .\) Similar to Exercise \(61,\) a formula can be found that will minimize the area of a cap that holds a specified volume. a. Solve the volume formula for the variable \(r\) b. Substitute the resulting expression for \(r\) into the surface area formula and simplify. The result is a formula for surface area given solely in terms of the volume \(V\) and the height \(h\). c. Assume the volume of the spherical cap is \(500 \mathrm{cm}^{3} .\) Use a graphing calculator to graph the resulting function on an appropriate window, and use the graph to find the height \(h\) that will result in a spherical cap with the smallest possible area, while still holding a volume of \(500 \mathrm{cm}^{3}\) d. Use this value of \(h\) and \(V=500 \mathrm{cm}^{3}\) to find the radius of the sphere.

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