# Sequences and Series

• Arithmetic sequences
1. Summation notation (4:26)
1. Writing using the summation (sigma) notation.
2. Writing using the summation (sigma) notation.
3.  Expanding .
2. Introduction to sequences (8:17) For the sequences and , the notation used to indicate a term of the sequence and a formula for it are discussed.
3. Introduction to arithmetic sequences (7:06) Recognizing arithmetic sequences, the initial term and their common difference.  Explicit and recursive formulas are discussed.
4. * Practice: Recursive formulas for arithmetic sequences. (4 problems)
5. * Practice: Extend arithmetic sequences. (4 problems)
6. * Practice: Explicit formulas for arithmetic sequences. (4 problems)
7. Explicit formulas for arithmetic sequences (6:16) Deriving a formula for the sequence .
• Arithmetic series
1. Arithmetic series intro (3:55) The sum of the first terms in the sequence .
2. Arithmetic series formula (7:46) The sum of the first terms in the sequence .
3. Arithmetic series (sigma notation) (7:01) Find .
4. Arithmetic series (sum expression) (6:46) Find .
5. Arithmetic series (recursive formula) (5:20) Given that and , find the sum of the first terms of the sequence.
6. * Practice: Arithmetic series. (4 problems)