Math Problem Statement

Simplify and determine the general term for the series: (-2/2) + (6/5) + (10/10) + (14/15) + ...

Solution

The series depicted in your image is:

22+65+1010+1415+-\frac{2}{2} + \frac{6}{5} + \frac{10}{10} + \frac{14}{15} + \dots

Let's break it down and analyze its general pattern.

Observations:

  1. The numerator forms an arithmetic sequence: 2,6,10,14,2, 6, 10, 14, \dots, increasing by 4 each time.
    • General formula for the numerator: an=2+4(n1)=4n2a_n = 2 + 4(n - 1) = 4n - 2.
  2. The denominator forms an arithmetic sequence: 2,5,10,15,2, 5, 10, 15, \dots, increasing by 3,5,3, 5, \dots each time.
    • General formula for the denominator: dn=n(n+1)/2d_n = n(n + 1) / 2, which corresponds to triangular numbers.

General Term of the Series:

The nn-th term of the series can be expressed as: an=4n2n(n+1)/2.a_n = \frac{4n - 2}{n(n + 1)/2}.

Simplify: an=4n2n(n+1)2=2(4n2)n(n+1)=8n4n(n+1).a_n = \frac{4n - 2}{\frac{n(n + 1)}{2}} = \frac{2(4n - 2)}{n(n + 1)} = \frac{8n - 4}{n(n + 1)}.

Further simplify: an=8n4n(n+1)=8n+14n.a_n = \frac{8n - 4}{n(n + 1)} = \frac{8}{n + 1} - \frac{4}{n}.

Thus, the series can be written as a telescoping sum: n=1(8n+14n).\sum_{n=1}^\infty \left( \frac{8}{n + 1} - \frac{4}{n} \right).

Would you like me to compute the sum or investigate its convergence?

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Arithmetic Sequences
Series
Telescoping Series

Formulas

General term of the numerator: a_n = 4n - 2
General term of the denominator: d_n = n(n + 1) / 2
Telescoping series: Sum of (8/(n + 1) - 4/n)

Theorems

Telescoping Series

Suitable Grade Level

Undergraduate Level or Advanced High School