The document discusses arithmetic sequences, highlighting the concept of common difference and providing examples. It includes formulas for calculating the sum of an arithmetic sequence and distinguishes between arithmetic and geometric series. Specific examples of sequences are given to illustrate these concepts.

4. Common
difference is 4
or d = 4
17-13=4
13-9=4
17-13=4

5. 9,_____,_____,_______,_______
9+ -4=5
5
5+ -4=1
-1
1+ -4=-3
-3
-3+ -4=-9
-7

6. Last term first term No.of
terms
Common
difference

9. SUM OF ARITHMETIC SEQUENCE
𝑺𝒏=
𝒏
𝟐
[𝟐 𝒂+(𝒏−𝟏 ) 𝒅 ]
Where;
sum of the arithmetic sequence
= first term
D= common difference
n= total number of terms in the sequence
= last term of the sequence
𝑺𝒏=
𝒏
𝟐
[ 𝒂𝟏 +𝒂𝒏 ]

10. Find the sum of the first 10 terms
of the arithmetic sequence
-4, -1, 2, 5

11. Find the sum of the first 10 terms
of the arithmetic sequence whose
1st
term is -4 and whose 10th
term
is 23.

13. Last term
first term
No. of terms

17. Let’s determine if the
sequence is arithmetic or
geometric
If geometric, it has
common ratio while
arithmetic it has
common difference

18. 1. 3, 7, 11, 15,…
Arithmetic Sequence

19. 2. 28, 23, 18, 13,…
Arithmetic Sequence

20. 3. 3, 6, 12, 24, 48, 96, ...
Geometric Sequence

21. 4. 1, 3, 9, 27, 81, ...
Geometric Sequence

22. 5. -17, -13, -9, -5,…
Arithmetic Sequence