Math Problem Statement

Evaluate the telescoping series: ∑ (1/n^3 - 1/(n+1)^3) from n = 1 to infinity.

Solution

The provided image presents the following series:

n=1(1n31(n+1)3)\sum_{n=1}^{\infty} \left( \frac{1}{n^3} - \frac{1}{(n+1)^3} \right)

This is a telescoping series, where terms from successive summations cancel each other out, leaving only a few terms in the final sum.

Step-by-step approach:

  1. Express the partial sum: Consider the partial sum up to a finite value NN:

    SN=n=1N(1n31(n+1)3)S_N = \sum_{n=1}^{N} \left( \frac{1}{n^3} - \frac{1}{(n+1)^3} \right)

    By expanding the terms for n=1n = 1 to n=Nn = N, we can see that the majority of terms cancel out (since for each nn, 1(n+1)3\frac{1}{(n+1)^3} cancels with 1n3\frac{1}{n^3} from the next term).

  2. Cancellation of terms: The first term from n=1n = 1 is 113=1\frac{1}{1^3} = 1, and the last term after cancellation is 1(N+1)3\frac{1}{(N+1)^3}. Therefore, the partial sum simplifies to:

    SN=11(N+1)3S_N = 1 - \frac{1}{(N+1)^3}

  3. Take the limit as NN \to \infty: Now, we compute the limit of SNS_N as NN approaches infinity:

    limNSN=limN(11(N+1)3)=10=1\lim_{N \to \infty} S_N = \lim_{N \to \infty} \left( 1 - \frac{1}{(N+1)^3} \right) = 1 - 0 = 1

Thus, the sum of the series is:

1\boxed{1}

Let me know if you would like more details or have any questions.

Here are 5 related questions for further exploration:

  1. How does a telescoping series differ from a geometric series?
  2. What conditions ensure the convergence of a telescoping series?
  3. Can all series be simplified into a telescoping form? Why or why not?
  4. What is an example of a divergent series, and how does it compare to this one?
  5. How does the sum of an infinite geometric series compare to that of a telescoping series?

Tip: When evaluating telescoping series, always look for cancellations between consecutive terms, as this often leads to significant simplification!

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Math Problem Analysis

Mathematical Concepts

Series
Telescoping Series
Limits
Convergence

Formulas

Telescoping sum: S_N = ∑ (1/n^3 - 1/(n+1)^3)
Limit of the sum: lim N→∞ S_N = 1 - (1/(N+1)^3)

Theorems

Telescoping series
Limit of a converging sequence

Suitable Grade Level

College-level calculus or advanced high school math