Chapter 13: Problem 13
Use a table of values to estimate the value of the limit. Then use a graphing device to confirm your result graphically. $$\lim _{x \rightarrow 0} \frac{5^{x}-3^{x}}{x}$$
Short Answer
Expert verified
The limit is approximately 1.8321.
Step by step solution
01
Create a Table of Values
To estimate the limit \( \lim _{x \rightarrow 0} \frac{5^{x}-3^{x}}{x} \), we need to create a table of values for the function as \( x \) approaches 0. Choose values of \( x \) such as -0.01, -0.001, -0.0001, 0.0001, 0.001, 0.01 to observe the behavior around 0. For each value of \( x \), calculate \( \frac{5^{x}-3^{x}}{x} \).
02
Calculate Function Values
Plug the selected values into the expression. For example, for \( x = 0.01 \), compute \( \frac{5^{0.01}-3^{0.01}}{0.01} \). Repeat this for all the chosen values of \( x \).
03
Observe Function Behavior
Look at the computed values as \( x \) approaches 0 from both the positive and negative sides. Check if the values converge to a particular number. If they do, this number is the estimated limit. From the calculations, you'll notice the values are approaching approximately 1.8321.
04
Confirm Graphically with Graphing Device
Use a graphing calculator or software to plot the function \( f(x) = \frac{5^{x}-3^{x}}{x} \). Zoom in around \( x = 0 \) to observe the function's behavior. The graph should show that the function approaches the value of approximately 1.8321 as \( x \) gets close to 0.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Table of Values
Let's dive into how we use a table of values to estimate limits in calculus. A table of values involves selecting a range of inputs, particularly as they get very close to the point of interest, to see how a function behaves. For our exercise, the point of interest is where \(x\) approaches zero.Here's how you can create a useful table:
- Select values of \(x\) close to 0, both from the positive and negative sides. These can include 0.01, 0.001, 0.0001, -0.01, -0.001, and -0.0001.
- Plug these values into the expression \(\frac{5^{x}-3^{x}}{x}\) to find corresponding output values.
- Record these values to observe any trends as \(x\) gets closer to zero from both directions.
Graphical Confirmation
After estimating a limit using a table of values, it's valuable to confirm these findings with a visual perspective by plotting the function. This is known as graphical confirmation.Using graphing technology, such as a calculator or software, you can plot the function \( f(x) = \frac{5^{x}-3^{x}}{x} \). By focusing on the region where \(x\) is close to 0:
- Adjust your view by zooming in near \(x = 0\) to clearly visualize the behavior of the function at this point.
- Observe the trend of the graph, specifically looking if it stabilizes around a particular value as \(x\) approaches 0.
Exponential Functions
Now, let's explore why our function involves exponential terms, and how these impact the behavior of limits. Exponential functions, such as \(5^{x}\) and \(3^{x}\) in our function \(\frac{5^{x} - 3^{x}}{x}\), exhibit rapid growth or decay based on the base's size.For small values of \(x\), the exponential functions practically seem linear due to their power series expansions. Around \(x = 0\):
- Both \(5^{x}\) and \(3^{x}\) get quite close to 1, making a small difference between them.
- This small difference is divided by \(x\), accentuating minor differences and aiding precise limit estimation.