Chapter 2: Problem 48
Sketch the graph of \(f\) $$f(x)=\left\\{\begin{array}{ll} -1 & \text { if } x \text { is an integer } \\ -2 & \text { if } x \text { is not an integer } \end{array}\right.$$
Short Answer
Expert verified
Discrete points at \(y = -1\) for integers; a continuous line at \(y = -2\) for non-integers.
Step by step solution
01
Understand the Function
The function \( f(x) \) is a piecewise function: it takes the value \(-1\) if \(x\) is an integer and \(-2\) if \(x\) is not an integer. This behavior will influence drawing two different levels on the graph.
02
Identify Integer Values
Recognize that integer values are numbers like \(..., -3, -2, -1, 0, 1, 2, 3, ...\). For these values of \(x\), \(f(x) = -1\). Each plotted point for these integers on the graph should be marked at a level \(y = -1\).
03
Plot Integer Points
Plot points such as \((-3, -1)\), \((-2, -1)\), \((-1, -1)\), \((0, -1)\), \((1, -1)\), \((2, -1)\), \((3, -1)\), and so forth. These points should appear as dots on the graph line \(y = -1\).
04
Identify Non-Integer Values
Non-integer values include numbers such as \(-3.5, 2.1, \pi, \sqrt{2},\) etc. For these values of \(x\), the function assigns \(f(x) = -2\).
05
Plot Non-Integer Values
For non-integer values, the output is \(-2\), creating a densely packed line at \(y = -2\). This line will not contain gaps and should be smoothly continuous alongside the points plotted at \(y = -1\) for integers.
06
Connect Points and Lines
The graph includes a dotted line of discrete points at \(y = -1\) for integers and a solid continuous line at \(y = -2\) for all non-integers. Ensure the scattered nature of integer outputs and continuous nature of non-integer outputs is visually clear.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graph Sketching
Graph sketching is a crucial skill that allows us to visualize functions and understand their behavior. For piecewise functions, the graph is often split into sections based on different conditions. Here, we're working with a function that changes based on whether the input is an integer or not.
The integer values form discrete points, easily spotted when plotted. Non-integer values, on the other hand, create a continuous line. Keeping these traits in mind makes sketching accurate and straightforward.
- For integer values, the function reaches a certain level.
- For non-integers, it settles on a different level.
The integer values form discrete points, easily spotted when plotted. Non-integer values, on the other hand, create a continuous line. Keeping these traits in mind makes sketching accurate and straightforward.
Integer Values
Integer values are whole numbers including negatives, zero, and positives, like \\(..., -3, -2, -1, 0, 1, 2, 3, ...\). They stand out as distinct positions on the graph due to their discrete nature. In our function:
- Whenever \(x\) is an integer, \(f(x)\) assigns the value \ \(-1\).
- These points appear only at the \(y = -1\) level on the graph.
- Use points like \ \((-3, -1), (-2, -1), \ldots\).
- These create a horizontal line of dots.
Non-Integer Values
Non-integer values include any number that isn't a whole number. This category features fractions and irrationals like \\(-3.5, 0.2, \pi\), and step up beyond simple integers. For our function:
- When \(x\) is a non-integer, \(f(x)\) yields \ \(-2\).
- This is represented as a continuous line on \(y = -2\).
- The non-integers should form an unbroken line across \(y = -2\).
- It highlights the difference between distinct and continuous parts of the graph.
Step Function
A step function jumps from one level to another, similar to climbing stairs. Each "step" reflects a sudden change in value, not a smooth transition. In our scenario:
- The function \(f(x)\) behaves like a step due to its integer and non-integer outputs.
- For integers, the function is a "step" on the \(y = -1\) level.
- For non-integers, it "steps" down to \(y = -2\).