1. 11.5 Arithmetic Sequence.notebook April 11, 2013
Arithmetic Sequences
Write a formula to find the nth term of the sequence.
2 5 8 11 d=
How many differences are there in between 5 terms?
To find the fifth term we can start with the first term: 2 and add the common difference 3 four times.
But what if you needed to find the 100th term?
How many differences would there be?
Start with the first term:

2. 11.5 Arithmetic Sequence.notebook April 11, 2013
2. Find a formula for the nth term of the sequence:
3, 7, 11, 15 . . . .
a1 = d =
What term are we trying to find?
How many differences are between the terms?
The general form of an arithmetic sequence is

3. 11.5 Arithmetic Sequence.notebook April 11, 2013
3. Find t17 for the sequence: 3, 7, 11, 15 . . .

4. 11.5 Arithmetic Sequence.notebook April 11, 2013
4. Find t23 for the arithmetic sequence in which t2 = 4 and t5 = 22.
Write formulas for both t2 and t5.

5. 11.5 Arithmetic Sequence.notebook April 11, 2013
The arithmetic mean between two numbers is the average of the two numbers.
5. Find the arithmetic mean of 4 and 9.
Arithmetic means are the terms between two given terms of an arithmetic sequence.
We can find 2 or more arithmetic means between two terms.
6. Insert four arithmetic means between 15 and 50.
Out line the sequence. Four arithmetic means places 4 terms between 15 and 60.
15, ___, ___, ___, ___, 50
In this sequence, 15 is the first term (t ) and 50 is the sixth term (t ).
1 6