Text of 8.2: Arithmetic Sequences and Partial Sums ... 8.2: Arithmetic Sequences and Partial Sums Objectives...
8.2: Arithmetic Sequences and
Partial Sums
Objectives
SWBAT
•Recognize, write, and find the nth terms of arithmetic sequences.
•Find the nth partial sums of arithmetic sequences.
•Use arithmetic sequences to model and solve real-life problems.
Vocabulary/Key Concepts
Arithmetic Sequence Common Difference
Sum of a Finite Arithmetic Sequence
1. an =
4
5
n +12
1 2 3 4 5 6 7 8 9 10n
an
Use the table feature of a graphing utility to find the first 10 terms
of the sequence.
3. 1,3,5,7,...,199
4. −10,−9,−8,...,50
2. 1+ 4 + 7 +10 +13+16 +19
Find the sum of the finite arithmetic sequence.
Sum of Finite Arithmetic Seq.
Sn =
n
2
a1 + an( )
6. n
n=51
100
∑ − n
n=1
50
∑
7. 1000 − n( )
n=0
250
∑
5. 2n
n=1
100
∑
Find the partial sum without a graphing utility.
Sum of Finite Arithmetic Seq.
Sn =
n
2
a1 + an( )
9. 10.5 + 0.025 j( )
j=1
200
∑8. 50 − 2n( )
n=0
50
∑
Use a graphing utility to find the partial sum.
10. Number of Logs Logs are stacked in a pile, as shown in the
figure. The row has 15 logs and the bottom row has 24 logs. How
many logs are in the pile?
