Find the sum of each infinite geometric series. 1 + 1/3 + 1/9 + 1/27 + ...
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- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
9. Sequences, Series, & Induction
Geometric Sequences
Problem 39
Textbook Question
Find the sum of each infinite geometric series. 3 + 3/4 + 3/42 + 3/43 + ...
Verified step by step guidance1
Identify the first term \( a \) of the infinite geometric series. In this series, the first term is \( 3 \).
Determine the common ratio \( r \) by dividing the second term by the first term. Here, \( r = \frac{3/4}{3} = \frac{1}{4} \).
Verify that the absolute value of the common ratio \( |r| < 1 \) to ensure the series converges. Since \( \frac{1}{4} < 1 \), the series converges.
Use the formula for the sum of an infinite geometric series: \[ S = \frac{a}{1 - r} \], where \( a \) is the first term and \( r \) is the common ratio.
Substitute the values of \( a = 3 \) and \( r = \frac{1}{4} \) into the formula to express the sum \( S \) without calculating the final value.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Infinite Geometric Series
An infinite geometric series is the sum of infinitely many terms where each term is found by multiplying the previous term by a constant ratio. It has the form a + ar + ar² + ar³ + ..., where 'a' is the first term and 'r' is the common ratio.
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Common Ratio
The common ratio 'r' in a geometric series is the factor by which each term is multiplied to get the next term. It is found by dividing any term by its preceding term. For the series to converge, the absolute value of 'r' must be less than 1.
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Sum of an Infinite Geometric Series
If the absolute value of the common ratio is less than 1, the infinite geometric series converges, and its sum can be calculated using the formula S = a / (1 - r), where 'a' is the first term and 'r' is the common ratio.
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