Chapter 4: Problem 44
Graph the function \(f(x)=3^{x}\) in the window \([-1,2]\) by \([-1,8],\) and estimate the slope of the graph at \(x=0\).
Short Answer
Expert verified
Plot the points, draw the curve, and estimate the slope at \(x=0\) to be around 2.
Step by step solution
01
- Understand the function
Recognize that the function to be graphed is an exponential function given by \(f(x)=3^x\). Exponential functions have rapid rates of increase.
02
- Identify the window
The graph should be plotted in the window where \(x\) ranges from [-1, 2] and \(y\) ranges from [-1, 8]. This sets the limits for the axes.
03
- Make a table of values
Choose values for \(x\) within the window and compute corresponding \(y\) values. For example: \(\begin{array}{ccc} x & = & -1 & 0 & 1 & 2 \ f(x) & = & 3^{-1} & 3^0 & 3^1 & 3^2 \ \text{Result} & = & \frac{1}{3} & 1 & 3 & 9 \end{array}\).
04
- Plot the calculated points
Plot the points from the table on the graph: (-1, \(\frac{1}{3}\)), (0, 1), (1, 3), (2, 9).
05
- Draw the graph
Connect the dots smoothly with a curve to represent the function. The graph of an exponential function should show an increasing curve.
06
- Estimate the slope at \(x=0\)
To estimate the slope at \(x=0\), look at how much \(y\) changes as \(x\) changes around 0. For finite differences, the slope \(\frac{\triangle y}{\triangle x}\) near \(x=0\) can be approximated. \((1-0) \text{ and } (3-1)= \frac{2}{1}=2\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Exponential Function
An exponential function is a type of mathematical function that shows rapid rates of increase or decrease. It follows the form \(f(x) = a^x\), where \(a\) is a constant base that is greater than 0. In this case, the function is \(f(x) = 3^x\). Exponential functions are important because they model many natural phenomena, such as population growth, radioactive decay, and interest calculations.
The key characteristics of exponential functions include:
The key characteristics of exponential functions include:
- A base greater than 1 results in growth.
- The curve is always increasing or decreasing, never flat.
- The rate of change accelerates as \(x\) increases or decreases, leading to very steep curves.
Slope Estimation
Slope estimation involves determining how much the \(y\) value of a function changes as the \(x\) value changes. This is particularly useful for understanding the behavior of a graph at specific points. For the function \(f(x) = 3^x\), estimating the slope at \(x=0\) tells us how steep the graph is at that point.
To estimate the slope at \(x = 0\), we use nearby points on the graph. In our step-by-step solution, we looked at the points (0, 1) and (1, 3). Slope is calculated using the formula \(\frac{\triangle y}{\triangle x} = \frac{y_2 - y_1}{x_2 - x_1} \)
Substituting \(y_2 = 3, y_1 = 1, x_2 = 1, x_1 = 0\), we get: \( \frac{3 - 1}{1 - 0} = 2 \)
This tells us that at \(x = 0\), the graph is rising with a slope of 2, indicating a fairly steep increase at that point.
To estimate the slope at \(x = 0\), we use nearby points on the graph. In our step-by-step solution, we looked at the points (0, 1) and (1, 3). Slope is calculated using the formula \(\frac{\triangle y}{\triangle x} = \frac{y_2 - y_1}{x_2 - x_1} \)
Substituting \(y_2 = 3, y_1 = 1, x_2 = 1, x_1 = 0\), we get: \( \frac{3 - 1}{1 - 0} = 2 \)
This tells us that at \(x = 0\), the graph is rising with a slope of 2, indicating a fairly steep increase at that point.
Graphing Techniques
Graphing exponential functions involves several key techniques to ensure the graph is accurate and easy to interpret.
- First, choose appropriate window settings for both \(x\) and \(y\) values. In this case, we used \([-1, 2]\) for \(x\) and \([-1, 8]\) for \(y\). These ranges ensure the key points of the graph are visible.
- Second, compute specific values of the function for chosen \(x\) values and list them in a table. This step provides the coordinates you need for plotting.
- Third, plot the points on graph paper or a digital plotting tool. Ensure each point is accurately placed according to its \(x\) and \(y\) values.
- Lastly, connect the plotted points smoothly. The curve should match the increasing or decreasing nature of the exponential function. For \(f(x) = 3^x\), the curve increases rapidly.
Coordinate Plotting
Coordinate plotting is essential for creating accurate graphs of functions. It involves using coordinates (x, y) to place points correctly on a graph.
When plotting the exponential function \(f(x) = 3^x\):
When plotting the exponential function \(f(x) = 3^x\):
- First, choose your \(x\) values within the given window, which for our exercise is \([-1, 2]\).
- Second, calculate the corresponding \(y\) values using the function. For example, at \(x = -1\), \(f(x) = 3^{-1} = \frac{1}{3}\). At \(x = 0\), \(f(x) = 3^0 = 1\).
- Third, write these coordinates down. Enlist all pairs such as \((-1, \frac{1}{3}), (0, 1), (1, 3), (2, 9)\).
- Finally, plot these coordinates carefully on the graph. For instance, the point (2, 9) means moving horizontally to 2 on the x-axis and vertically to 9 on the y-axis before marking the point.