Section 11.2Arithmetic Sequences and Series

Arithmetic Sequences & SeriesArithmetic Sequences Arithmetic Series

• 2, 4, 6, 8,…

• 9, 5, 1, -3,…

• 7, 11/2, 4, 5/2,…

• 2 + 4 + 6 + 8 + 10

• 9 + 5 + 1 – 3 – 7 - 11

• 7 + 11/2 + 4 + 5/2

Rule for an Arithmetic Sequence•The nth term of an arithmetic sequence

with first term a1 and common difference of d is given by:

)1(1 ndaanDon’t leave it in this form after you plug-in values.

)1(32 nan 332 nan 13 nan

If the first term 2 and common difference is 3

The Sum of a Finite Arithmetic Series

•The sum of the first n terms of an arithmetic series is:

2

)( 1 nn

aanS

Finding the Sum of a Series in Summation Notation•Recall formulas from 11.1:

n

n1

1

n nni

1 2

)1(

Assignment

•11.2 Practice C#1-17, 20,22-25