Quadratic Sequences and Other Sequence Types
This page provides a comprehensive overview of various sequence types, with a focus on quadratic sequences and methods for finding their nth terms. It covers essential concepts in sequence analysis, making it valuable for students studying mathematics.
The document begins by introducing different types of sequences:
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Arithmetic (Linear) Sequences: These have a constant difference between consecutive terms.
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Quadratic Sequences: The second difference between consecutive terms is constant.
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Geometric Sequences: Each term after the first is found by multiplying the previous one by a fixed, non-zero number called a common ratio.
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Fibonacci Sequence: Each number is the sum of the two preceding ones.
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Square Numbers: The product of an integer with itself.
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Triangular Numbers: A series obtained by continued summation of natural numbers.
Definition: A quadratic sequence is a sequence where the second difference between consecutive terms is constant.
The page then delves into the methods for finding the nth term of sequences:
For linear sequences:
- The document provides an example of finding the nth term, explaining how to use the common difference to formulate the expression.
Example: For the sequence 6, 12, 18, 24, the nth term is 6n.
For quadratic sequences:
- The general rule for the nth term of a quadratic sequence is presented as an² + bn + c.
- A step-by-step method for finding the values of a, b, and c is demonstrated.
Highlight: The second difference in a quadratic sequence is always twice the 'a' value in the nth term formula.
The document concludes with an alternative method for finding the nth term of quadratic sequences by comparison, using square numbers as an example.
Example: For the sequence 9, 16, 25..., the nth term is T(n) = n².
This comprehensive guide serves as an excellent resource for students learning about finding the nth term of a quadratic sequence and other sequence types, providing clear explanations and practical examples.