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C H A PT E R 1

Calculator Notes for the TI-Nspire and TI-Nspire CAS

Note 1A: Reentry
If you are not currently in the Calculator application, press c and choose
Calculator. Evaluate an expression. To perform an operation on the result of the expression you just evaluated, press any mathematical operation key and type an expression. The result of the previously evaluated expression will appear as “Ans” until you press ·.

You can enter the previous line into an expression by pressing /-.
For example, evaluate an expression, press /q/-, and type –1 before pressing ·.
You can also recall and edit a previous expression. Press £ to highlight the entry you want to recall and press ·. Use the NavPad to move across the expression and enter new characters. To delete characters, press .. When you are finished, press · to recalculate the revised expression.

Note 1B: Recursion
The command /- allows you to use the result of your last calculation in your next calculation. Also, if you press · without pressing another key, the handheld will recompute the last expression. Using these two commands together gives you a recursion machine.
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Note 1B: Recursion (continued)

TI-Nspire and TI-Nspire CAS

If you are not currently in the Calculator application, press c and choose
Calculator. First, type the starting value of a sequence and press ·. This value represents u1. Then type the rule, pressing /- for “Ans” in place of un Ϫ 1. Press · repeatedly to generate the sequence. These screens show the sequence. u1 ϭ 47 un ϭ 2unϪ1 Ϫ 8 where n Ն 2

You can generate several sequences at once. This is useful when you want to keep track of the term numbers of a sequence, or when you want to keep track of several related sequences. Use braces, { and }, to enclose the sequences, and separate the value for each sequence with a comma. Use
Ans[1], Ans[2], and so on, to refer to the previous values. This example shows the starting values 1, 2000, and 470. Each time · is pressed, the first sequence is increased by 1, the second sequence is decreased by 50, and the third sequence is increased by 40. You can think of the first sequence as n.
The other two sequences can be described by the formulas: u1 ϭ 2000 un ϭ unϪ1 Ϫ 50 where n Ն 2

and

u1 ϭ 470 un ϭ unϪ1 ϩ 40 where n Ն 2

Discovering Advanced Algebra Calculator Notes for the Texas Instruments TI-Nspire and TI-Nspire CAS

CHAPTER 1

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TI-Nspire and TI-Nspire CAS