7. When each term in a sequence is
found by multiplying the previous
term by a constant, it is called
Geometric Sequence
8. Each term is multiplied by 2 to get the
preceding terms.
The 1st term (a1)is -1.
To obtain the second term, the common
ratio (r) is multiplied to a1.
11. Geometric Sequence
EXAMPLES
1 2 3 4
Mr. Rivera wants to save money on his
bank account. He decided to double the
amount of money that he will deposit every
month. He started to save ₱ 100 on his
bank account. About how much will he save
after 5 months?
Given:
a1=₱ 100
r = 2
n=5
a5=?
Solution:
an= a1
.rn-1
a5 = ₱ 100 (2)5-1
a5 = ₱ 100 (2)4
a5 = ₱ 100 (16)
a5 = ₱ 1600
Answer:
₱1600
12. Geometric Sequence
EXAMPLES
1 2 3 4
Given that a1 = -3.5, r = 4
and an = -224, find the
value of n.
Given:
a1=-3.5
r = 4
an=-224
n=?
Solution:
an= a1
.rn-1
-224=-3.5(4n-1)
64=4n-1
22n-2=26
2n-2=6
2n=6+2
n=4
Answer:
4
13. is a type of mean or average, which indicates
the central tendency or typical value of a set
of numbers using the product of their values.
Geometric Mean
That means you multiply a bunch of numbers
together, and then take the nth root, where n
is the number of values you just multiplied.
14. The first and the last terms of a geometric
sequence are called Extremes
The terms between them are called Means
5, 25, 125, 625
20. Geometric Mean
EXAMPLES
1 2 3 4
Find r and the missing
terms in the Geometric
Sequence (2,_,_,54)
r=3
2, 2(3),2(3)(3), 54
2, 6, 18, 54
Answers:
r = 3
a2 = 6
a3 = 18
21. 1. Find the 9th term in the Geometric
Sequence 3, 9, 27, 81, 243.
2. Find the first term of a geometric
sequence whose fourth and seventh terms
are 108 and 2916.
3. Find two geometric means between 128
and 16.
22. Submitted by:
Richelle Mae E. Padilla
Angel Mae B. Ruiz
Reenie Trisha Vergara
Shemm L. Madrid
Marx Chryx Del Mundo