HP 39gs Sequence aplet, About the Sequence aplet, Getting started with the Sequence aplet

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Sequence aplet

About the Sequence aplet

The Sequence aplet allows you to explore sequences.

You can define a sequence named, for example, U1:

•in terms of n

•in terms of U1(n–1)

•in terms of U1(n–2)

•in terms of another sequence, for example, U2(n)

•in any combination of the above.

The Sequence aplet allows you to create two types of graphs:

–A Stairsteps graph plots n on the horizontal axis and Un on the vertical axis.

–A Cobweb graph plots Un–1on the horizontal axis and Un on the vertical axis.

Getting started with the Sequence aplet

The following example defines and then plots an expression in the Sequence aplet. The sequence illustrated is the well-known Fibonacci sequence where each term, from the third term on, is the sum of the preceding two terms. In this example, we specify three sequence fields: the first term, the second term and a rule for generating all subsequent terms.

However, you can also define a sequence by specifying just the first term and the rule for generating all subsequent terms. You will, though, have to enter the second term if the hp39gs is unable to calculate it automatically. Typically if the nth term in the sequence depends on n–2, then you must enter the second term.

Sequence aplet 6-1