This document provides information about geometric sequences including their key properties and formulas. It defines a geometric sequence as one where the ratio between consecutive terms is constant, known as the common ratio. Formulas given include the recursive formula an = an-1r and explicit formula an = a1rn-1. Examples are provided for identifying geometric sequences and using the formulas to find missing terms. Additional notes state that arithmetic sequences have linear graphs while geometric sequences have exponential graphs.

1. Homework Questions

2. Geometric Sequences

3. Geometric Sequences
 In a geometric sequence, the ratio between
consecutive terms is constant.
 This ratio is called the common ratio.
 To find r:
stterm
ndterm
1
2

4. Geometric, Arithmetic, Neither?
(find the next 2 terms if so)
1. 5, 15, 45, 135…
2. 15, 30, 45, 60…
3. 6, -24, 96, -384…
4. 8, 20, 32, 44…

5. Geometric Sequences Formulas
 Recursive Formula
 an = an-1 r
 Explicit Formula
 an = a1 rn-1
•
•

6. Find the 19th
term…
1. 11, 33, 99, 297…
2. 20, 17, 14, 11, 8…

7. FYI - Graphs
 Arithmetic Graphs are linear
 Geometric Graphs are exponential

8. Geometric Mean
 Geometric Mean =
3. 20, _____, 80
4. 3, ____, 18, 75
5. 28, ____, 5103
numbersproductof 2

9. Homework
 Worksheet!

10. Homework
 Worksheet!