1. 11.2 Arithmetic Sequences

2. An arithmetic sequence is defined as

3. Show that the following sequence is arithmetic
Show that the following sequence is arithmetic. Find the first term and the common difference.
Common difference does not depend on n, therefore the sequence is arithmetic.

4. Theorem nth Term of an Arithmetic Sequence

5. Find the 20th term of the sequence
4, 1, -2, -5,

6. The 6th term of an arithmetic sequence is equal to 31 and the 19th is 109. Find the first term and the common difference. Find the recursive formula for the sequence.
We get a system of equations.

9. Theorem Sum of n Terms of an Arithmetic Sequence