Understanding Series in Algebra

A series is the sum of the terms of a sequence. Series are important in algebra for understanding patterns and summing values.

What is a Series?

A series is the sum of the terms in a sequence.

It can be finite or infinite.

Types of Series
  • Arithmetic series: The difference between terms is constant.
  • Geometric series: Each term is multiplied by a constant to get the next.
Formulas
  • Arithmetic: \( S_n = \frac{n}{2}(a_1 + a_n) \)
  • Geometric: \( S_n = a_1 \frac{1 - r^n}{1 - r} \) for \( r \neq 1 \)
Infinite Series

An infinite series has an infinite number of terms.

Some infinite series converge to a value; others diverge.

Practice Problems

  1. Find the sum of the first 10 terms of the arithmetic series: 2, 5, 8, ...
  2. Find the sum of the geometric series: 3, 6, 12, 24 (4 terms)
  3. Does the series \( 1 + \frac{1}{2} + \frac{1}{4} + \cdots \) converge?

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