Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
9. Sequences, Series, & Induction
Geometric Sequences
Problem 35b
Textbook Question
In Exercises 31–36, find the indicated sum. Use the formula for the sum of the first n terms of a geometric sequence.
6 Σ (i = 1) (1/2)^(i + 1)![Sum of a geometric sequence from i=1 to 6 for (1/2)^(i+1).](https://lightcat-files.s3.amazonaws.com/problem_images/eb8a8506b806ff10-1678243841634.jpg)
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1
Identify the sequence as a geometric sequence with the general term \( a_i = \left(\frac{1}{2}\right)^{i+1} \).
Determine the first term \( a_1 \) by substituting \( i = 1 \) into the general term: \( a_1 = \left(\frac{1}{2}\right)^{1+1} = \left(\frac{1}{2}\right)^2 \).
Identify the common ratio \( r \) of the geometric sequence, which is \( \frac{1}{2} \).
Use the formula for the sum of the first \( n \) terms of a geometric sequence: \( S_n = a_1 \frac{1-r^n}{1-r} \), where \( n = 6 \).
Substitute \( a_1 = \left(\frac{1}{2}\right)^2 \), \( r = \frac{1}{2} \), and \( n = 6 \) into the sum formula to find \( S_6 \).
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