Big Ideas Math Integrated I, 2016
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Big Ideas Math Integrated I, 2016 View details
6. Recursively Defined Sequences
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Exercise 8 Page 318

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:

Practice makes perfect
We are asked to write the first 6 terms of a sequence, given a recursive rule. a_1&=10 a_n&=a_(n-1)-5, for n ≥ 2

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!