Chapter 2: Problem 42
Make a table listing ordered pairs for each function. Then sketch the graph and state the domain and range. $$f(x)=\left\\{\begin{aligned} 3 & \text { for } x<0 \\ 3+\sqrt{x} & \text { for } x \geq 0 \end{aligned}\right.$$
Short Answer
Expert verified
Ordered pairs: (-3, 3), (-2, 3), (-1, 3), (0, 3), (1, 4), (4, 5). Domain: (-∞, ∞). Range: [3, ∞).
Step by step solution
01
Identify the Function Sections
The given function has two sections. For values of \(x < 0\), the function is a constant value \(f(x) = 3\). For values of \(x \geq 0\), the function is \(f(x) = 3 + \sqrt{x}\).
02
Create Ordered Pairs for \(x < 0\)
For the section \(x < 0\), regardless of the value of \(x\), \(f(x)\) is always 3. So, let's select some values for \(x \) such as -3, -2, -1, and create ordered pairs: (-3, 3), (-2, 3), (-1, 3).
03
Create Ordered Pairs for \(x \geq 0\)
For the section \(x \geq 0\), use the function \(f(x) = 3 + \sqrt{x}\). Select some values for \(x\) such as 0, 1, 4, and create ordered pairs: (0, 3), (1, 4), (4, 5).
04
Combine All Ordered Pairs
Combine the ordered pairs from the two sections: (-3, 3), (-2, 3), (-1, 3), (0, 3), (1, 4), (4, 5).
05
Sketch the Graph
Plot the combined ordered pairs on a coordinate plane. The graph will have a horizontal line at \(y=3\) for \(x < 0\), and a curve starting from (0, 3) upward for \(x \geq 0\) following \(y = 3 + \sqrt{x}\).
06
Determine the Domain
The domain of the function includes all real numbers, \( (-\infty, \infty) \), as it is defined for both \(x < 0\) and \(x \geq 0\).
07
Determine the Range
The range of the function is found from the values that \(f(x)\) can take. For \(x < 0\), \(f(x) = 3\). For \(x \geq 0\), \(f(x) = 3 + \sqrt{x}\) which means \(f(x)\) starts from 3 and increases. Therefore, the range is \([3, \infty)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
domain and range
The domain of a function is the set of all possible input values (x-values) that the function can accept. In this case, our function has two parts: one for values where x is less than 0, and another for values where x is greater than or equal to 0. Both parts together cover all possible real numbers. Hence, the domain of this function is all real numbers, which we write as \((-\infty, \infty)\).
On the other hand, the range is the set of all possible output values (y-values) that the function can produce. For our function, when x is less than 0, the output (y-value) is always 3. When x is greater than or equal to 0, the output is 3 plus the square root of x. As x gets larger, so does the output. Hence, the range starts from 3 and goes to infinity. This can be written as \[ [3, \infty) \].
On the other hand, the range is the set of all possible output values (y-values) that the function can produce. For our function, when x is less than 0, the output (y-value) is always 3. When x is greater than or equal to 0, the output is 3 plus the square root of x. As x gets larger, so does the output. Hence, the range starts from 3 and goes to infinity. This can be written as \[ [3, \infty) \].
graphing functions
When it comes to graphing functions, it's important to plot ordered pairs on a coordinate plane. To do this, you need to carefully analyze the function given. Our function has two parts, and we'll graph each one separately before combining them.
For values of x less than 0, the function is a constant 3. This means that the graph will be a horizontal line at y=3 for all negative x-values. For x greater than or equal to 0, the function is 3 plus the square root of x. This part of the graph will start at the point (0, 3) and curve upwards as x increases. Points like (1, 4) and (4, 5) help visualize this curve.
To graph the whole function, plot all the ordered pairs: (-3, 3), (-2, 3), (-1, 3), (0, 3), (1, 4), and (4, 5). Connect the points for x less than 0 with a straight horizontal line, and connect the points for x greater than or equal to 0 with a smooth curve following the shape of y=3 + \( \sqrt{x} \). This method ensures a clear and accurate graph of the function.
For values of x less than 0, the function is a constant 3. This means that the graph will be a horizontal line at y=3 for all negative x-values. For x greater than or equal to 0, the function is 3 plus the square root of x. This part of the graph will start at the point (0, 3) and curve upwards as x increases. Points like (1, 4) and (4, 5) help visualize this curve.
To graph the whole function, plot all the ordered pairs: (-3, 3), (-2, 3), (-1, 3), (0, 3), (1, 4), and (4, 5). Connect the points for x less than 0 with a straight horizontal line, and connect the points for x greater than or equal to 0 with a smooth curve following the shape of y=3 + \( \sqrt{x} \). This method ensures a clear and accurate graph of the function.
ordered pairs
Ordered pairs are simply pairs of numbers that represent points on a graph, written in the form (x, y). To fully represent a piecewise function graphically, we need to find these ordered pairs for different sections of the function.
In our case, we first looked at the section of the function where x is less than 0. Any x-value in this section produces a y-value of 3. We chose x-values like -3, -2, and -1 to form the ordered pairs (-3, 3), (-2, 3), and (-1, 3).
For the section where x is greater than or equal to 0, we used the function y = 3 + \( \sqrt{x} \). Choosing x-values like 0, 1, and 4, we calculated the corresponding y-values to form ordered pairs: (0, 3), (1, 4), and (4, 5).
Combining these ordered pairs helps us plot the function more easily and see how it behaves for all values of x, allowing for a clear understanding of the entire function's shape and range.
In our case, we first looked at the section of the function where x is less than 0. Any x-value in this section produces a y-value of 3. We chose x-values like -3, -2, and -1 to form the ordered pairs (-3, 3), (-2, 3), and (-1, 3).
For the section where x is greater than or equal to 0, we used the function y = 3 + \( \sqrt{x} \). Choosing x-values like 0, 1, and 4, we calculated the corresponding y-values to form ordered pairs: (0, 3), (1, 4), and (4, 5).
Combining these ordered pairs helps us plot the function more easily and see how it behaves for all values of x, allowing for a clear understanding of the entire function's shape and range.