Math Problem Statement

2 + 4 + 8 + 16 +32+... what is the sum of the geometric series

Solution

The given series is a geometric series:
2+4+8+16+32+2 + 4 + 8 + 16 + 32 + \dots

In a geometric series, each term is multiplied by a constant ratio to get the next term. Here, the first term a=2a = 2 and the common ratio r=42=2r = \frac{4}{2} = 2.

If the series is infinite, the sum of an infinite geometric series is given by the formula: S=a1rwhere r<1.S = \frac{a}{1 - r} \quad \text{where} \ |r| < 1. However, since r=2r = 2, which is greater than 1, the series does not converge to a finite sum. Therefore, the sum of this infinite geometric series does not exist.

If the series is finite (e.g., stopping after a certain number of terms), the sum of the first nn terms of a geometric series is: Sn=arn1r1.S_n = a \frac{r^n - 1}{r - 1}. For your series, with a=2a = 2 and r=2r = 2, the sum of the first nn terms is: Sn=22n121=2(2n1).S_n = 2 \frac{2^n - 1}{2 - 1} = 2(2^n - 1).

Do you want to calculate the sum for a specific number of terms, or further details on how this works?

Related questions:

  1. What is the formula for the sum of an infinite geometric series with r<1|r| < 1?
  2. How does the common ratio affect the convergence of a geometric series?
  3. Can a divergent series be used in real-world applications?
  4. How do you derive the formula for the sum of a finite geometric series?
  5. What happens if the common ratio is negative in a geometric series?

Tip: For any geometric series, always check the common ratio to determine if the series converges or diverges.

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Math Problem Analysis

Mathematical Concepts

Geometric Series
Sequences and Series

Formulas

Sum of infinite geometric series: S = a / (1 - r) for |r| < 1
Sum of finite geometric series: S_n = a * (r^n - 1) / (r - 1)

Theorems

Geometric Series Convergence Theorem

Suitable Grade Level

Grades 9-12