Math Problem Statement

Konvergiert die Folge f_n = (-1)^n / n?

Solution

The question is asking whether the sequence fn=(1)nnf_n = \frac{(-1)^n}{n} converges.

To determine the convergence of this sequence, let's analyze the general behavior of fn=(1)nnf_n = \frac{(-1)^n}{n}.

Solution:

  1. The term (1)n(-1)^n alternates between 11 and 1-1, so the sequence oscillates in sign.
  2. However, as nn increases, the term 1n\frac{1}{n} tends to 00.
  3. Since fnf_n is of the form (1)nn\frac{(-1)^n}{n}, the oscillations get smaller as nn grows because 1n0\frac{1}{n} \to 0.

Therefore, despite the oscillation in signs, the sequence converges to 00 as nn \to \infty.

Conclusion:

The answer to the question is:

  • a. Ja (Yes)

Would you like a more detailed explanation of the convergence?


Here are 5 related questions to expand your understanding:

  1. What is the difference between absolute and conditional convergence?
  2. How does the behavior of an alternating sequence differ from a non-alternating one in terms of convergence?
  3. What is the definition of convergence for a sequence?
  4. What is the general method to test if a sequence converges to zero?
  5. How would the convergence change if the sequence was 1n2\frac{1}{n^2} instead of (1)nn\frac{(-1)^n}{n}?

Tip: To test for convergence, observe the behavior of the sequence as nn approaches infinity.

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Math Problem Analysis

Mathematical Concepts

Sequences and Series
Convergence of Sequences
Alternating Series

Formulas

f_n = (-1)^n / n

Theorems

Limit of a Sequence
Alternating Series Test

Suitable Grade Level

Grades 11-12