Chapter 2: Problem 30
In Problems \(9-34\), sketch the graph of the given piece wise-defined function. Find any \(x\) - and \(y\) intercepts of the graph. Give any numbers at which the function is discontinuous. $$ y=|\sqrt{x}-2| $$
Short Answer
Expert verified
The function is continuous for \( x \geq 0 \), with a y-intercept at (0, 2) and an x-intercept at (4, 0).
Step by step solution
01
Understand the Function
The function given is a piecewise function defined by the expression \( y = | \sqrt{x} - 2|\). This indicates that the function first applies the square root operation to \( x \), then subtracts 2, and finally takes the absolute value.
02
Define the Domain
Since the function involves \( \sqrt{x} \), the input \( x \) must be non-negative. This means the domain of the function is \( x \geq 0 \).
03
Identify Points of Discontinuity
The absolute value function does not introduce discontinuities, and \( \sqrt{x} \) is continuous for \( x \geq 0 \). Therefore, the function is continuous for all \( x \geq 0 \).
04
Find the y-intercept
To find the y-intercept, set \( x = 0 \). Substituting into the function gives \( y = |\sqrt{0} - 2| = |-2| = 2 \). This means the y-intercept is at (0, 2).
05
Find the x-intercept(s)
To find the x-intercepts, set \( y = 0 \) and solve \( |\sqrt{x} - 2| = 0 \). This simplifies to \( \sqrt{x} - 2 = 0 \), which gives \( \sqrt{x} = 2 \), leading to \( x = 4 \). Thus, the x-intercept is at (4, 0).
06
Graph the Function
Sketch the graph. Start by considering \( y = \sqrt{x} - 2 \) for \( x \geq 0 \). The absolute value means the graph of \( y = \sqrt{x} - 2 \) will flip over the x-axis wherever it dips below the axis. Plot key points: (0, 2), (4, 0), and note the graph is above the x-axis.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Function Continuity
When we discuss function continuity, we're looking at how smooth a function's graph is without any abrupt breaks or jumps. In this case, the function given is a piecewise function of the form \( y = |\sqrt{x} - 2| \). This function employs three operations: taking a square root, subtracting a number, and taking the absolute value.
Continuity depends on each of these operations:
Continuity depends on each of these operations:
- The square root function, \( \sqrt{x} \), is continuous for non-negative values of \( x \). This means no gaps or jumps for \( x \geq 0 \).
- Subtracting 2 from \( \sqrt{x} \) shifts the graph downward by 2 units, but doesn't affect continuity.
- The absolute value function, \( |u| \), where \( u = \sqrt{x} - 2 \), reflects any negative values of the inside operation over the x-axis, but also does not cause discontinuities.
Domain of a Function
The domain of a function is all the possible values that the independent variable, usually \( x \), can take for the function to output real numbers. The function \( y = |\sqrt{x} - 2| \) depends heavily on the square root operation.
For \( \sqrt{x} \), \( x \) must be non-negative, meaning \( x \geq 0 \). Square roots of negative numbers do not produce real results, therefore any negative values are excluded from our domain.
This leaves us with a domain expressed as:
For \( \sqrt{x} \), \( x \) must be non-negative, meaning \( x \geq 0 \). Square roots of negative numbers do not produce real results, therefore any negative values are excluded from our domain.
This leaves us with a domain expressed as:
- \( x \geq 0 \)
x-intercepts and y-intercepts
The intercepts of a graph are points where the graph crosses the axes. Identifying intercepts provides quick insights into the behavior of the function.
**Finding the y-intercept**
At the y-axis, \( x = 0 \). By substituting \( x = 0 \) into the function \( y = |\sqrt{0} - 2| \), we find \( y = |-2| = 2 \). Hence, the y-intercept is at the point (0, 2).
**Finding the x-intercept(s)**
For x-intercepts, \( y = 0 \). Setting the function equal to zero gives us \( |\sqrt{x} - 2| = 0 \). Solving this equation, we find \( \sqrt{x} = 2 \), and by squaring both sides, we conclude \( x = 4 \). Thus, the x-intercept is at the point (4, 0).
Remember, these intercepts are critical checkpoints in understanding how the function behaves and where it interacts with the axis.
**Finding the y-intercept**
At the y-axis, \( x = 0 \). By substituting \( x = 0 \) into the function \( y = |\sqrt{0} - 2| \), we find \( y = |-2| = 2 \). Hence, the y-intercept is at the point (0, 2).
**Finding the x-intercept(s)**
For x-intercepts, \( y = 0 \). Setting the function equal to zero gives us \( |\sqrt{x} - 2| = 0 \). Solving this equation, we find \( \sqrt{x} = 2 \), and by squaring both sides, we conclude \( x = 4 \). Thus, the x-intercept is at the point (4, 0).
Remember, these intercepts are critical checkpoints in understanding how the function behaves and where it interacts with the axis.
Graphing Functions
Graphing a function requires plotting key points and drawing the curve that represents the function on a coordinate plane. The function \( y = |\sqrt{x} - 2| \) can be understood by grasping how each component affects the graph.
**Initial Sketch**
First, consider the graph of \( y = \sqrt{x} - 2 \). This graph typically starts at (0, -2) and slopes upward, passing through the x-intercept at (4, 0). However, the crucial aspect of graphing \( y = |\sqrt{x} - 2| \) is the absolute value function.
**Absolute Value Effect**
Anywhere \( \sqrt{x} - 2 \) would be negative, it is flipped over the x-axis by the absolute value operation. This creates a 'V' shape in the graph, as it reflects the curve above the x-axis.
**Key Points for Graphing**
**Initial Sketch**
First, consider the graph of \( y = \sqrt{x} - 2 \). This graph typically starts at (0, -2) and slopes upward, passing through the x-intercept at (4, 0). However, the crucial aspect of graphing \( y = |\sqrt{x} - 2| \) is the absolute value function.
**Absolute Value Effect**
Anywhere \( \sqrt{x} - 2 \) would be negative, it is flipped over the x-axis by the absolute value operation. This creates a 'V' shape in the graph, as it reflects the curve above the x-axis.
**Key Points for Graphing**
- Start at the y-intercept (0, 2).
- Plot the x-intercept at (4, 0).
- Trace the mirrored graph to reflect over the y-axis symmetry.