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Ch. 8 - Sequences, Induction, and Probability
Blitzer - College Algebra 8th Edition
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Capitolo 9, Problema 49

Write out the first three terms and the last term. Then use the formula for the sum of the first n terms of an arithmetic sequence to find the indicated sum.
∑i=11004i\(\sum\)_{i=1}^{100} 4i

Guida verificata passo dopo passo
1
Identify the arithmetic sequence given by the general term: \(a_i = 4i\), where \(i\) ranges from 1 to 100.
Write out the first three terms by substituting \(i = 1, 2, 3\) into the formula: \(a_1 = 4(1)\), \(a_2 = 4(2)\), and \(a_3 = 4(3)\).
Find the last term by substituting \(i = 100\) into the formula: \(a_{100} = 4(100)\).
Recall the formula for the sum of the first \(n\) terms of an arithmetic sequence: \(S_n = \frac{n}{2} (a_1 + a_n)\), where \(a_1\) is the first term and \(a_n\) is the last term.
Substitute \(n = 100\), the first term \(a_1\), and the last term \(a_{100}\) into the sum formula to express the sum \(S_{100}\).

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Arithmetic Sequence

An arithmetic sequence is a list of numbers where each term after the first is found by adding a constant difference to the previous term. For example, in the sequence 4, 8, 12, ..., each term increases by 4. Understanding this helps identify the pattern and calculate specific terms.
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General Term of an Arithmetic Sequence

The nth term of an arithmetic sequence can be found using the formula a_n = a_1 + (n - 1)d, where a_1 is the first term and d is the common difference. This formula allows you to find any term in the sequence without listing all previous terms.
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Sum of the First n Terms of an Arithmetic Sequence

The sum of the first n terms of an arithmetic sequence is given by S_n = n/2 (a_1 + a_n), where a_1 is the first term and a_n is the nth term. This formula efficiently calculates the total sum without adding each term individually.
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