Chapter 6: Problem 67
Evaluate the series. $$\sum_{k=1}^{4} \frac{1}{k}$$
Short Answer
Expert verified
The sum of the series \(\sum_{k=1}^{4} \frac{1}{k}\) is approximately 2.083
Step by step solution
01
Identify the series type
The given series is of the form \(\sum_{k=1}^{4} \frac{1}{k}\), which is a harmonic series. In a harmonic series, each term is the reciprocal of a positive integer.
02
Calculate each term of the series
In order to calculate the sum of the series, evaluate each term in the series:For \(k = 1\), \(\frac{1}{k} = 1\),For \(k = 2\), \(\frac{1}{k} = 0.5\),For \(k = 3\), \(\frac{1}{k} = \frac{1}{3}\) = approximately 0.333,For \(k = 4\), \(\frac{1}{k} = 0.25\).
03
Add all terms together
Now, add all the terms together to find the sum of the series. \(\sum_{k=1}^{4} \frac{1}{k} = 1 + 0.5 + 0.333 + 0.25 = 2.083 \)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Series Evaluation
When evaluating a series, it is crucial to first recognize the type of series you are dealing with. In the provided problem, we have a harmonic series. To evaluate a series:
- Identify the formula or pattern each term follows.
- Determine the value or range of values of the index involved, here it is denoted by "k" ranging from 1 to 4.
- Calculate each term in the series using the given formula.
- Add up all calculated terms to find the total sum of the series.
Reciprocal
A reciprocal refers to the multiplicative inverse of a number. Simply put, for a fraction or a number "x," the reciprocal is calculated as \(\frac{1}{x}\). In this exercise, each term of the series is the reciprocal of a positive integer. For example, the reciprocal of 1 is \(\frac{1}{1} = 1\), 2 is \(\frac{1}{2} = 0.5\), and so on.
Understanding reciprocals is fundamental in solving harmonic series, as they form the backbone of calculating each term:
Understanding reciprocals is fundamental in solving harmonic series, as they form the backbone of calculating each term:
- Recognize that a reciprocal effectively translates an integer to its "one-over" form, crucial for harmonic series.
- Use reciprocals to transform any integer into a fraction, which is in turn summed up over the series.
Sum Series
A sum series involves adding the values of terms in the sequence over a specified range. In the case of our exercise, the range is from 1 to 4, and each term is expressed as the reciprocal of its index number.
To find the sum of our series:
To find the sum of our series:
- Calculate each term, which we've done previously as 1, 0.5, \(\frac{1}{3}\), and 0.25.
- Add these calculated terms together.
- The final addition, \(1 + 0.5 + \frac{1}{3} + 0.25\), gives the approximate sum of 2.083.
Sequence and Series
Considering both sequences and series is essential to understanding their structure and evaluation. A sequence refers to a list of numbers following a particular pattern, while a series is the sum of such a sequence.
In the exercise example, the sequence \(a_1, a_2, a_3, a_4\) is given by \(1, \frac{1}{2}, \frac{1}{3}, \frac{1}{4}\). This sequence is the base of the series.
In the exercise example, the sequence \(a_1, a_2, a_3, a_4\) is given by \(1, \frac{1}{2}, \frac{1}{3}, \frac{1}{4}\). This sequence is the base of the series.
- Recognize the sequential pattern of the terms, here as the reciprocals of integers.
- Convert the sequence into a series by summing the terms according to the specified index range.