Chapter 11: Problem 32
State whether the sequence converges as \(n \rightarrow \infty\); if it does limit, $$\int_{0}^{1 / n} \cos e^{x} d x$$
Short Answer
Expert verified
The sequence converges to 0 as \(n \rightarrow \infty\).
Step by step solution
01
Understanding the Integral Under Consideration
The integral under consideration is \(\int_{0}^{1/n} \cos(e^x) dx\). As the upper limit of this integral depends on \(n\), this integral will yield a sequence of numbers as \(n\) varies.
02
Analyzing the Limit of the Upper Bound
The upper limit of the integral is \(1/n\). As \(n\) approaches infinity, \(1/n\) approaches 0. Therefore, evaluating the integral as \(n\) approaches infinity is the equivalent of evaluating the integral from 0 to 0.
03
Evaluating the Integral
The integral from 0 to 0 of any function is 0, since the limits of integration are identical and thus describe a region of zero width. Therefore, the limit of the sequence as \(n\) approaches infinity is 0.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Sequence Convergence
When we talk about a sequence in mathematics, we're referring to a list of numbers in a specific order. Sequence convergence means that as the sequence progresses towards infinity, the numbers get closer and closer to a fixed value, called the limit. In the context of calculus sequences, we often analyze sequences that arise from functions or operations over a series of numbers.
The sequence we're dealing with originates from the definite integral: \[\int_{0}^{1/n} \cos(e^x) \, dx\]
This sequence is based on the varying upper limit, which is dependent on variable \(n\). As \(n\) increases, \(1/n\) decreases, changing the integral’s range. Hence, for different \(n\), the sequence takes on different values. By investigating these values as \(n\) approaches infinity, we can determine whether the sequence converges to a certain number. In this case, our sequence approaches a limit of 0 as \(n\) becomes very large.
The sequence we're dealing with originates from the definite integral: \[\int_{0}^{1/n} \cos(e^x) \, dx\]
This sequence is based on the varying upper limit, which is dependent on variable \(n\). As \(n\) increases, \(1/n\) decreases, changing the integral’s range. Hence, for different \(n\), the sequence takes on different values. By investigating these values as \(n\) approaches infinity, we can determine whether the sequence converges to a certain number. In this case, our sequence approaches a limit of 0 as \(n\) becomes very large.
- Convergence is finding the potential fixed value a sequence inches towards as it progresses.
- Determining this limit helps us understand the long-term behavior of a sequence.
- A sequence is said to converge if such a fixed value exists and is finite as \(n\) approaches infinity.
Definite Integral
A definite integral can be thought of as a tool to calculate the area under a curve over a specific interval on the graph of a function. The definite integral provides a precise quantification of this area, yielding a specific number. The symbol\[\int_a^b f(x) \, dx\]indicates the integral of function \(f(x)\) from the lower bound \(a\) to the upper bound \(b\).
For our specific exercise, the integral \[\int_{0}^{1/n} \cos(e^x) \, dx\]describes the accumulated area under the curve of \(\cos(e^x)\) between the limits 0 and \(1/n\). As \(n\) varies, these limits change, causing the area calculation to also vary, generating a sequence. But because this integral's upper and lower bounds approach each other as \(n\) approaches infinity, the calculated area approaches zero.
For our specific exercise, the integral \[\int_{0}^{1/n} \cos(e^x) \, dx\]describes the accumulated area under the curve of \(\cos(e^x)\) between the limits 0 and \(1/n\). As \(n\) varies, these limits change, causing the area calculation to also vary, generating a sequence. But because this integral's upper and lower bounds approach each other as \(n\) approaches infinity, the calculated area approaches zero.
- The definite integral calculates how much "space" exists under a curve between two points.
- It's a cornerstone concept in calculus and crucial in understanding sequences related to areas.
- Different upper and lower bounds mean the integral equates to different sequences.
Integral Limits
In calculus, the terms upper and lower limits of an integral determine the range over which a function is evaluated. These limits are critical because they define the boundary and size of the region under a curve that we are interested in. The result of a definite integral depends largely on these limits.
For our problem, the integral's limits are 0 and \(1/n\). As \(n\) tends to infinity, the upper limit \(1/n\) shrinks towards 0, effectively squeezing our area of interest into a tiny region. This change results in an integral value that's bound to zero because the integral is essentially taken over a zero-width interval.
For our problem, the integral's limits are 0 and \(1/n\). As \(n\) tends to infinity, the upper limit \(1/n\) shrinks towards 0, effectively squeezing our area of interest into a tiny region. This change results in an integral value that's bound to zero because the integral is essentially taken over a zero-width interval.
- Integral limits set the framework over which we measure the area under a curve using a definite integral.
- Changing these limits impacts how much "space" you calculate between the curve and the axis.
- When the interval's width collapses to zero, so does the area beneath the curve, affecting the result significantly.