1. Arithmetic Sequences
In an arithmetic sequence, the difference between consecutive terms is constant.
The difference is called the common difference.
To find d: 2nd term – 1st term

2. Arithmetic?
2, 4, 8, 16
6, 12, 18
48, 45, 42
2, 5, 7, 12

3. Arithmetic Sequence Formulas
Recursive Formula
an = an-1 + d
Explicit Formula
an = a1 + (n-1)d
an = nth term
a1 = 1st term
n = number of terms
d = common difference

4. Examples Find the 20th term of each sequence 213, 201, 189, 177…
.0023, .0025, .0027…

5. More examples
Find the 17th term of the sequence:
a16 = 18, d = 5

6. Find the missing term Use arithmetic mean = average! 84, _______, 110
24, _______, 57