Chapter 3: Problem 83
(a) Graph \(f(x)=|x-3|-3\) using transformations. (b) Find the area of the region that is bounded by \(f\) and the \(x\) -axis and lies below the \(x\) -axis.
Short Answer
Expert verified
The area of the region below the x-axis is 9 square units.
Step by step solution
01
Understand the Base Graph
The base graph here is the absolute value function, denoted as \( g(x) = |x| \). This graph forms a 'V' shape with its vertex at the origin (0,0).
02
Apply Horizontal Shift
The function \( f(x) = |x-3| - 3 \) includes a horizontal shift. The term \( x-3 \) indicates a shift 3 units to the right. Therefore, the vertex of the 'V' shape now moves to (3,0).
03
Apply Vertical Shift
Next, note the \( -3 \) term outside the absolute value. This causes a vertical shift downward by 3 units. The new vertex of the graph becomes (3, -3).
04
Plot the Transformed Graph
Using the transformations, plot the function \( f(x) = |x-3| - 3 \) by starting at the new vertex (3, -3) and drawing the usual 'V' shape.
05
Determine Where the Graph Crosses the x-axis
To find intersections with the x-axis, set \( f(x) = 0 \):\[ |x-3| - 3 = 0 \Rightarrow |x-3| = 3 \Rightarrow x - 3 = 3 \text{ or } x - 3 = -3 \Rightarrow x = 6 \text{ or } x = 0 \]. Thus, the graph crosses the x-axis at x = 6 and x = 0.
06
Calculate the Bounded Area Below the x-axis
The region below the x-axis and bounded by the graph can be visualized as an inverted triangle with base from x = 0 to x = 6. The height of the triangle is the distance from the x-axis to the lowest point of the graph, which is 3 units down (from y = 0 to y = -3). Calculate the area: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 6 \times 3 = 9 \text{ square units} \]
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
absolute value function
The absolute value function, denoted as \( g(x) = |x| \), is fundamental in understanding graph transformations. This function creates a 'V' shaped graph, symmetric about the y-axis. The vertex, or the tip of the 'V', is positioned at the origin (0,0). The graph reflects across the y-axis, making it identical on both sides. When dealing with absolute value functions, keep in mind its unique property: it always outputs non-negative values for any input. This property is key in understanding how transformations affect the graph.
horizontal shift
A horizontal shift changes the position of the graph left or right along the x-axis. It's represented inside the function argument. For instance, in the function \( f(x) = |x-3| - 3 \), the term \( x-3 \) means the graph of \( |x| \) shifts 3 units to the right. Think of it as relocating the starting point of your graph. This transformation does not alter the shape of the graph; it simply moves the vertex. By comparing \( |x| \) and \( |x-3| \), you'll see the 'V' shape has slid from (0,0) to (3,0).
vertical shift
A vertical shift moves the graph up or down along the y-axis. It's reflected as a constant term added or subtracted outside the function. For the function \( f(x) = |x-3| - 3 \), the \( -3 \) outside the absolute value function indicates a vertical shift downward by 3 units. This transformation alters the y-value of the vertex, moving it from (3,0) to (3, -3). Remember, the shape remains unchanged; we just adjust the graph’s position vertically. Imagine lifting or lowering the entire 'V' shape along the y-axis: it now starts from (3,-3).
area under curve
Finding the area under a curve involves calculating the space between the graph and the x-axis within a range of x-values. For our function \( f(x) = |x-3| - 3 \), the area of interest is below the x-axis, forming a triangle between x = 0 and x = 6. The graph crosses the x-axis at these points. The height of this inverted triangle is from y = 0 to y = -3, which is 3 units. We use the formula for the area of a triangle: \[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]. Here, base is the distance between x = 0 and x = 6, totaling 6 units. Thus, the area is \( \frac{1}{2} \times 6 \times 3 = 9 \) square units.