| What is the
10th term of the sequence 1, 3, 7,
15...? |
Give a brief summary of a few
important keys on the calculator:
- how to clear,
- use of the
 key
- awareness of the Ans key for calling
up previous results.
Show the class how to use the Ans
button to create a sequence, and then ask to produce these themselves:
| Sequence |
Key
presses |
| 8, 16, 24, 32, 40, … |
8
8
... |
| 5, 13, 21, 29, 37, … |
5
8
... |
| 89, 80, 71, 62, 53, … |
89
 9
... |
| 0.5, 1, 1.5, 2, … |
0.5
0.5
... |
| 41, 36, 31, 26, … |
41
5
... |
| 2, 4, 8, 16, … |
2
 2
... |
| 10, 100, 1000, 10000, … |
10
10
... |
| 5, 11, 23, 47, 95... |
5
2
1
... |
| |
|
Typical screen displays:
These sequences of key presses, which
tell the calculator how to work out the next term, and the next term, and so
on, are describing term-to-term rules. Figure out the key presses and
term-to-term rules for these sequences, and hence find the 10th term:
| Sequence |
Key
presses |
Term-to-term
rule |
| 1, - 2, 4, - 8, 16, … |
1
 2
... |
x
-2 |
| 1, 1/2, 1 /4, 1 /8, 1 /16, 1 /32,
… |
1
 2
... |
÷
2 |
| 1, 0.5, 0.25, 0.125, 0.0625 …
|
1
0.5
... |
x
0.5 |
| 2, 3, 5, 9, 17... |
2
2
1
... |
x 2 -
1 |
| 1, 2, 5, 14, 41... |
1
3
1
... |
x 3 -
1 |
| 10, 8, 6, 4, 2 ... |
10
2
... |
- 2
|
| |
|
|
|
