Geometric Sequence Calculator

Geometric SequenceCalculator

Calculate nth term, sum of series, infinite series, and geometric sequence properties with step-by-step solutions. Perfect for mathematics, algebra, and series analysis.

Geometric Sequence Calculator
Calculate nth term, sum of series, infinite series, and geometric sequence properties with step-by-step solutions

Why Use Our Geometric Sequence Calculator?

Comprehensive geometric sequence calculations with detailed explanations

Nth Term Calculation

Find any term in a geometric sequence using the formula aₙ = a₁ × r^(n-1)

Sum of Series

Calculate the sum of finite and infinite geometric series with convergence analysis

Common Ratio Analysis

Find common ratio, first term, and analyze convergence properties

Step-by-Step Solutions

Detailed explanations and mathematical methods for every calculation

How Geometric Sequence Calculator Works

Understanding geometric sequences and series calculations

1

Enter Parameters

Input the first term, common ratio, term number, or other required values for your geometric sequence calculation.

2

Select Calculation Type

Choose from nth term, sum of series, infinite series, finding common ratio, or finding first term calculations.

3

Get Results

Receive detailed results with step-by-step solutions, convergence analysis, and sequence visualization.

Geometric Sequence Formulas

Nth Term Formula

aₙ = a₁ × r^(n-1)

Sum of Series

Sₙ = a₁(1 - r^n)/(1 - r)

Infinite Series

S∞ = a₁/(1 - r) when |r| < 1

Geometric Sequence Examples

Common geometric sequence patterns and their applications

Basic Geometric Sequences

Sequence: 2, 6, 18, 54, ...r = 3

5th term = 2 × 3^4 = 162

Sequence: 1, 2, 4, 8, ...r = 2

Sum of first 5 terms = 1(1-2^5)/(1-2) = 31

Convergent Series

Sequence: 1, 1/2, 1/4, 1/8, ...r = 1/2

Infinite sum = 1/(1-1/2) = 2

Sequence: 100, 50, 25, 12.5, ...r = 0.5

Infinite sum = 100/(1-0.5) = 200

Frequently Asked Questions

Common questions about geometric sequences and series

What is a geometric sequence?

A geometric sequence is a sequence where each term after the first is found by multiplying the previous term by a constant called the common ratio. The general form is a₁, a₁r, a₁r², a₁r³, ...

How do I find the nth term of a geometric sequence?

Use the formula aₙ = a₁ × r^(n-1), where a₁ is the first term, r is the common ratio, and n is the term number you want to find.

What is the sum of a geometric series?

For a finite geometric series with n terms, the sum is Sₙ = a₁(1 - r^n)/(1 - r) when r ≠ 1. For an infinite geometric series, the sum is S∞ = a₁/(1 - r) when |r| < 1.

When does a geometric series converge?

An infinite geometric series converges when the absolute value of the common ratio is less than 1 (|r| < 1). If |r| ≥ 1, the series diverges.

What's the difference between arithmetic and geometric sequences?

In an arithmetic sequence, each term is obtained by adding a constant difference to the previous term. In a geometric sequence, each term is obtained by multiplying the previous term by a constant ratio.

How do I find the common ratio of a geometric sequence?

Divide any term by the previous term: r = aₙ/aₙ₋₁. Alternatively, if you know the first term and any nth term, you can use r = (aₙ/a₁)^(1/(n-1)).

Can the common ratio be negative?

Yes, the common ratio can be negative. This creates an alternating geometric sequence where terms alternate between positive and negative values.

What are real-world applications of geometric sequences?

Geometric sequences are used in compound interest calculations, population growth models, radioactive decay, computer algorithms, and many other exponential growth or decay scenarios.

How do I find the first term if I know the ratio and nth term?

Rearrange the nth term formula: a₁ = aₙ / r^(n-1). This gives you the first term when you know the common ratio, term number, and the value of that term.

What is the relationship between geometric sequences and exponential functions?

Geometric sequences are discrete versions of exponential functions. The nth term formula aₙ = a₁ × r^(n-1) is similar to the exponential function f(x) = a × r^x.

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Geometric Sequence Calculator - Calculate Nth Term, Sum & Series | The Calcs