1. Week 4
Warm Up
1) Geometric or Arithmetic?
-2, 4, -8, 16, -32, 64,…

2. Homework

3. I will identify term numbers and terms of sequences.
Geometry
Sequences Day 2
I will identify term numbers and terms of sequences.
Term
The value of the number in the sequence.
Terms
Ex 1
3, , 11, 15, 19
1st
2nd
3rd
4th
5th
Term #’s
Term #
The order in the sequence.

4. I will identify term numbers and terms of sequences.
Geometry
Sequences Day 2
I will identify term numbers and terms of sequences.
Term
The value of the number in the sequence.
Terms
Ex 1
3, , 11, 15, 19
1st
2nd
3rd
4th
5th
Term #’s
Term #
The order in the sequence.

5. 3, 7, 11, 15, 19, . . .
Term #
is read “t sub 1.” t1
means the first term is 3
t1 = 3
the second term is 7
t2 = 7
t3 = 11
the third term is 11

6. represents the nth term in the sequence
Ex 2
-6, -1, 4, 9, 14, . . . tn
represents the nth term in the sequence
is read “t sub n.”
if n = 1 then
tn = -6
if n = 3 then
tn = 4
if n = 6 then
tn = 19

7. Ex 3
-8, 1, 10, 19, 28, . . .
tn-1
represents the previous term to the nth term
if n = 2 then
tn-1 = -8
tn-2
represents two previous terms to the nth term
if n = 5 then
tn-2 = 10

8. represents the next term after the nth term
-6, -1, 4, 9, 14, . . .
tn+1
represents the next term after the nth term
if n = 2 then
tn+1 = 4
if n = 4 then
tn+2 = 19

9. an 2, 9, 16, 23, 30, . . . is read “a sub n.” it’s the same as t1
Ex 5
2, 9, 16, 23, 30, . . . an
is read “a sub n.”
it’s the same as t1
if n = 4
then an+2 = 37

10. Arithmetic or Geometric
Ex 6
-4, 12, -36, 108, -324, . . .
if n = 6 then
an-1 =
-324
if n = 6 then
an- 2 =
108
Arithmetic or Geometric
Starting with -4, multiply the previous number by -3 to get the next number.

11. Fibonacci Sequence
1, 1, 2, 3, 5, 8, 13, 21, 34, . . .
Rule?
Starting with one, the sum of the two previous terms equals the next term.

12. Review What is a recursive formula? -6, 12, -24, 48, -96, . . .
-6, 12, -24, 48, -96, . . .
Do: 1
if n = 8 then
an-3 =
Rule?
Handout – Sequences CW 1.2
Recursive Formulas
Assignment: