Chapter 9: Problem 24
Graph each polynomial function. Give the domain and range. $$ f(x)=3 x+2 $$
Short Answer
Expert verified
The graph is a straight line with domain \((-\infty, \infty)\) and range \((-\infty, \infty)\).
Step by step solution
01
- Identify the Type of Polynomial
Observe the given function: \( f(x) = 3x + 2 \). This is a linear polynomial, as it is in the form \( ax + b \).
02
- Determine the Slope and Intercept
In the function \( f(x) = 3x + 2 \), the coefficient of \( x \) is the slope (3), and the constant term (2) is the y-intercept. Thus, the slope is 3 and the y-intercept is 2.
03
- Plot the Y-Intercept
Start by plotting the y-intercept (0, 2) on the graph. This is the point where the line crosses the y-axis.
04
- Use the Slope to Plot Another Point
From the y-intercept, use the slope to find another point. A slope of 3 means that for every 1 unit increase in \( x \), \( y \) increases by 3 units. Moving 1 unit to the right from (0, 2) reaches (1, 5).
05
- Draw the Line
Draw a straight line through the points (0, 2) and (1, 5). This line represents the function \( f(x) = 3x + 2 \).
06
- State the Domain
For a linear polynomial, the domain consists of all real numbers (\( -\infty, \infty \)).
07
- State the Range
Similarly, since the line extends infinitely in both directions vertically, the range is also all real numbers (\( -\infty, \infty \)).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Polynomial Function
A polynomial function is a mathematical expression involving a sum of powers in one or more variables, multiplied by coefficients. In simple terms, it looks like a series of terms where each term is a constant multiplied by the variable raised to a non-negative integer power.
For example:
For example:
- 3x2 + 2x + 1
- 5x + 7
- x3 - 4x2 + 3x - 2
- 0 degree: Constant polynomial (e.g., 7)
- 1st degree: Linear polynomial (e.g., 3x + 2)
- 2nd degree: Quadratic polynomial (e.g., x2 - 4x + 4)
- 3rd degree: Cubic polynomial (e.g., x3 + 2x - 1)
Linear Polynomial
A linear polynomial is a polynomial of degree 1. This means it has the form f(x) = ax + b, where a and b are constants, and x is the variable. The highest power of x in this polynomial is 1.
For example, in the exercise f(x) = 3x + 2, this function is linear because it fits the form ax + b. Here, a = 3 and b = 2.
Key characteristics of a linear polynomial include:
For example, in the exercise f(x) = 3x + 2, this function is linear because it fits the form ax + b. Here, a = 3 and b = 2.
Key characteristics of a linear polynomial include:
- Slope: The coefficient of x, which determines the steepness of the line. In f(x) = 3x + 2, the slope is 3.
- Y-Intercept: The constant term, which is the point where the line crosses the y-axis. In our function, the y-intercept is 2.
- Graph: The graph of a linear polynomial is always a straight line.
Domain and Range
The domain and range are important concepts when discussing functions. They describe the set of possible input values and output values, respectively.
For a linear polynomial like f(x) = 3x + 2:
For a linear polynomial like f(x) = 3x + 2:
- Domain: The domain of a function is the set of all possible x-values that can be input into the function. Since you can input any real number into a linear polynomial, the domain is all real numbers, \(\(-\infty, \infty\)\).
- Range: The range is the set of all possible y-values the function can produce. For linear polynomials, as the line extends infinitely in both vertical directions, the range is also all real numbers, \(\(-\infty, \infty\)\).