6. Recursively Defined Sequences
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The given rule means that, after the first term of the sequence, every term a_n is the difference between the previous term a_(n-1) and 5.
Sequence: 10, 5, 0, - 5, - 10, and - 15
Graph:
To do so, we will use a table.
| n | a_n=a_(n-1)-5 | a_(n-1)-5 | a_n |
|---|---|---|---|
| 1 | a_1=10 | - | 10 |
| 2 | a_2=a_(2-1)-5 | a_1-5= 10-5 | 5 |
| 3 | a_3=a_(3-1)-5 | a_2-5= 5-5 | |
| 4 | a_4=a_(4-1)-5 | a_3-5= -5 | - 5 |
| 5 | a_5=a_(5-1)-5 | a_4-5=- 5-5 | - 10 |
| 6 | a_6=a_(6-1)-5 | a_5-5=- 10-5 | - 15 |
Therefore, the first 6 terms of the sequence are 10, 5, 0, - 5, - 10, and - 15. Let's graph these points!