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Lesson 18

Getting Started (Introduction to Sequence, continued)

We will begin with a very quick introduction to sequences. A general understanding of the terminology used in writing sequences will help you in using the Sequence application. As you learn about sequences in school, you will find the Sequence application particularly useful.

Sequences are defined with a useful notation that contains subscripts. We input a number from a set {1, 2, 3 …} to get a term in the sequence.

Notation (Mathematical language is interesting!)

a_n is read a sub n

a_k is read a sub k

The open form of an infinite sequence can be written as:

{ a₁, a₂, a₃, a₄, …, a_n, a_n+1, …}

The closed form of a sequence (if we can find one) is an equation that can be used to generate each term in the sequence.

For example,
If the closed form of a sequence is given by:
a_n=5-n
then the sequence can be found by replacing n with 1, then 2, then 3, …
For n=1, we have a₁=5-1=4
For n=2, we have a₂=5-2=3
For n=3, we have a₃=5-3=2
And so on!

Before beginning the practice exercises, open a word document, type in the following information and then save it as Lesson18 in your CASIO folder within My Documents:

• Date: (enter today's date)
• To: (put your instructor's name here)
• From: (put your name here)
• Re: Lesson 18