/*! 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 29 (a) Determine the \(x\) - and \(... [FREE SOLUTION] | 91Ó°ÊÓ

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(a) Determine the \(x\) - and \(y\) -intercepts and the excluded regions for the graph of the given function. Specify your results using a sketch similar to Figure \(16(a) .\) In Exercises \(31-34\) you will first need to factor the polynomial. (b) Graph each function. $$y=2 x(x-2)(x-1)$$

Short Answer

Expert verified
x-intercepts at x = 0, 1, 2; y-intercept at y = 0; no excluded regions.

Step by step solution

01

Determine x-intercepts

To find the x-intercepts, we set the equation equal to zero: \(y = 2x(x-2)(x-1) = 0\). Solve for \(x\) by setting each factor equal to zero: \(x = 0\), \(x - 2 = 0\), and \(x - 1 = 0\). This gives us the x-intercepts: \(x = 0\), \(x = 2\), and \(x = 1\).
02

Determine y-intercept

To find the y-intercept, we set \(x = 0\) in the equation: \(y = 2(0)(0-2)(0-1)\). This simplifies to \(y = 0\). Thus, the y-intercept is \(0\).
03

Identify excluded regions

For this polynomial function, there are no restrictions on the domain (such as division by zero), so there are no excluded regions.
04

Factor the polynomial

The polynomial is already factored as \(y = 2x(x-2)(x-1)\), no further factoring is needed.
05

Sketch the graph

Plot the x-intercepts at \(x = 0\), \(x = 1\), and \(x = 2\) on the x-axis. The y-intercept is also at \(y = 0\). The curve crosses the x-axis at these points.
06

Draw the graph shape

This polynomial is a cubic function, which typically starts below the x-axis, rises, dips below again, and then rises to finish above the x-axis. Considering the function's coefficients and intercepts, draw a rough sketch showing these movements across the intercepts.

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Key Concepts

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

x-intercept
The x-intercept(s) of a polynomial function are the points where the graph touches or crosses the x-axis. These occur where the value of the function, or the output, equals zero.
To find the x-intercepts of the function provided, you need to set the polynomial equal to zero:
\[ y = 2x(x - 2)(x - 1) = 0 \]By setting each factor equal to zero, we determine the values of \(x\) where the graph has its intercepts:
  • \(2x = 0\) which simplifies to \(x = 0\).
  • \(x - 2 = 0\) which simplifies to \(x = 2\).
  • \(x - 1 = 0\) which simplifies to \(x = 1\).
Thus, the x-intercepts of the function are \(x = 0\), \(x = 1\), and \(x = 2\). These points are where the graph will cross the x-axis. Each of these intercepts provides critical insight into the shape and direction of the polynomial graph.
Understanding this concept is essential for graphing functions and identifying the roots or solutions of polynomial equations.
y-intercept
A y-intercept is the point where the graph of a function crosses the y-axis. This is found by setting \(x = 0\) in the function, because the y-intercept occurs when the input is zero.
For the polynomial function given as:\[ y = 2x(x-2)(x-1) \]you can find the y-intercept by substituting \(0\) for \(x\):
\[ y = 2(0)(0-2)(0-1) \]When simplified, this equation gives:\[ y = 0 \]Thus, the y-intercept is \(0\), meaning that the graph of the polynomial passes through the origin.
This is a key feature of a graph, making it easier to sketch since it shows where the graph intersects vertically with the y-axis. Recognizing y-intercepts helps in understanding how a function behaves at initial or starting values.
polynomial factoring
Factoring a polynomial is the process of breaking down the polynomial into a product of simpler polynomials. This step is crucial when finding intercepts, graphing, or simplifying polynomials.
Factoring makes it easier to solve polynomial equations and understand the structure of the polynomial function. In the original exercise, the polynomial was already factored as: \[ y = 2x(x-2)(x-1) \]The given polynomial is presented in factored form, meaning no further breaking down into simpler components is needed. Each factor of the polynomial corresponds to an x-intercept, providing direct information about where the graph intersects with the x-axis.
  • The factor \(2x\) relates to the x-intercept \(x = 0\).
  • The factor \(x - 2\) relates to the x-intercept \(x = 2\).
  • The factor \(x - 1\) relates to the x-intercept \(x = 1\).
Understanding polynomial factoring enhances student proficiency in manipulating and analyzing polynomial expressions, paving the way for more advanced mathematical challenges.
cubic functions
Cubic functions are polynomial functions with the highest degree of three, meaning the largest exponent of the variable is three. These functions are characterized by an "S" shaped curve that can vary in direction based on the coefficients.
A standard cubic function can be expressed as:\[ y = ax^3 + bx^2 + cx + d \]The function in the exercise is:\[ y = 2x(x-2)(x-1) \]This cubic function has three roots as previously determined, and its graph typically passes through these roots, crossing the x-axis at those points. The general shape involves starting from either far above or below the x-axis, then crossing at each root, and extending to the opposite side of the x-axis, again far away.
For the function \(y = 2x(x-2)(x-1)\):
  • The function starts below the x-axis, as indicated by the negative x value among roots.
  • It rises, passing through \(x = 0\), dipping slightly after crossing \(x = 1\), and finally cutting through \(x = 2\) to ascend again.
Cubic functions' unique curves make them interesting and important to analyze, as they can model real-world phenomena that show initial rapid growth or decay followed by slower growth or eventual leveling off. Understanding cubic functions' behavior is vital in fields like physics, economics, and engineering.

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Most popular questions from this chapter

Find the \(x\) -coordinate of the vertex of the parabola \(y=(x-a)(x-b) .\) (Your answer will be in terms of the constants \(a \text { and } b .)\) Hint: It's easier here to rely on symmetry than on completing the square.

(a) Use a graphing utility to draw a graph of each function. (b) For each \(x\) -intercept, zoom in until you can estimate it accurately to the nearest one-tenth. (c) Use algebra to determine each \(x\) -intercept. If an intercept involves a radical, give that answer as well as a calculator approximation rounded to three decimal places. Check to see that your results are consistent with the graphical estimates obtained in part (b). $$N(t)=t^{7}+8 t^{4}+16 t$$

(a) Factor the expression \(4 x^{2}-x^{4}\). Then use the techniques explained in this section to graph the function defined by \(y=4 x^{2}-x^{4}\). (b) Find the coordinates of the turning points. Hint: As in previous sections, use the substitution \(x^{2}=t\).

The following table and scatter plot show global coal consumption for the years \(1990-1995\). $$\begin{array}{cc} \hline \text { Year } x & \text { Coal consumption } y \\ \hline x=0 \leftrightarrow 1990 & \text { (billion tons) } \\ \hline 0 & 3.368 \\ 1 & 3.285 \\ 2 & 3.258 \\ 3 & 3.243 \\ 4 & 3.261 \\ 5 & 3.311 \\ \hline \end{array}$$ (GRAPH CAN'T COPY) (a) Use a graphing utility to find a quadratic model for the data. Then use the model to make estimates for global coal consumption in 1989 and 1996 (b) Use the following information to show that, in terms of percentage error, the 1996 estimate is better than the 1989 estimate, but in both cases the percentage error is less than \(2 \% .\) The actual figures for coal consumption in 1989 and 1996 are 3.408 and 3.428 billion tons, respectively. (c) Use the model to project worldwide coal consumption in \(1998 .\) Then show that the percentage error is more than \(9 \%,\) given that the actual 1998 consumption was 3.329 billion tons.

How far from the origin is the vertex of the parabola \(y=x^{2}-6 x+13 ?\)

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