A geometric sequence is a sequence of numbers in which each term after the first is found by multiplying the previous term by a fixed, non-zero number called the common ratio. In other words, each term in a geometric sequence is obtained by multiplying the previous term by a constant factor.
The general form of a geometric sequence is: a, ar, ar^2, ar^3, ..., where 'a' is the first term, 'r' is the common ratio, and 'n' is the position of the term in the sequence.
For example, if the first term of a geometric sequence is 2 and the common ratio is 3, the sequence would be: 2, 6, 18, 54, ...
Geometric sequences have several important properties, including:
1. The nth term of a geometric sequence can be found using the formula: a_n = a * r^(n-1), where 'a_n' is the nth term, 'a' is the first term, 'r' is the common ratio, and 'n' is the position of the term in the sequence.
2. The sum of the first 'n' terms of a geometric sequence can be found using the formula: S_n = a * (1 - r^n) / (1 - r), where 'S_n' is the sum of the first 'n' terms, 'a' is the first term, 'r' is the common ratio, and 'n' is the number of terms in the sequence.
Geometric sequences are commonly used in mathematics, finance, and science to model exponential growth or decay. They are also used in various real-world applications, such as population growth, compound interest, and radioactive decay.