Comprehensive Guide to Patterns and Sequences in Mathematics
Explore patterns in nature and art, understand arithmetic and geometric sequences, learn the Fibonacci sequence, and solve real-world problems using mathematical sequences.
Learning Objectives
Describe patternsby inspection, including
in art and nature
Determine the next term in various
patterns including Fibonacci sequence
Identify the rule governing a pattern and
illustrate attributes of arithmetic and
geometric sequences
3.
Patterns in Art
andNature
Discover how patterns appear all around us in nature and
art
4.
What is a
Pattern?
Apattern is a repeated or predictable arrangement of
numbers, shapes, or objects. Patterns follow specific
rules that allow us to predict what comes next. They
can be visual (like shapes and colors) or numerical
(like number sequences).
Examples: 2, 4, 6, 8... or ...
▲ ● ▲ ● ▲ ●
5.
Recognizing
Patterns by
Inspection
Look forrepetition or regular changes in sequences
Notice increases or decreases in
numbers
Identify recurring shapes or colors. Example: 2, 4, 6,
8… (increasing by 2)
6.
Determining the
Next Termin
Patterns
To find the next term, identify the rule
connecting each term. Look at the pattern: 3, 6,
12, 24, ? Each term is double the previous term
(×2). Following this rule, the next term is 24 × 2 =
48!
Try it yourself: What comes next in 5, 10, 15, 20,
?
Understanding
the Fibonacci
Rule
The Fibonaccisequence follows a simple but
powerful rule: each term is the sum of the
two previous terms. Starting with 0 and 1,
we get:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34...
Interactive Challenge: What is the 10th Fibonacci
number?
9.
Identifying Pattern
Rules
Addition orsubtraction (arithmetic patterns)
Multiplication or division (geometric
patterns)
Alternating, repeating, or Fibonacci (recursive)
sequences
Example: Rule for 2, 4, 8, 16 is "multiply by 2"
10.
Arithmetic
Sequences:
Definition &
Attributes
An arithmeticsequence is a sequence where each
term is found by adding a constant value (called the
common difference) to the previous term. Key
attributes include the first term (a₁) and common
difference (d).
Example: 3, 7, 11, 15, … where d = 4
11.
Attributes of
Arithmetic Sequences
Illustrated
Generalterm formula: aₙ = a₁ + (n - 1)d
Constant difference between consecutive
terms
Linear growth or decline pattern. Example: For 3, 7, 11, 15...
find the 10th term: a₁₀ = 3 + (10-1)×4 = 39
12.
Classifications of
Sequence
FINITE SEQUENCE
Afinite sequence has a specific
number of terms – it has a
beginning and an end.
Example: 2, 4, 6, 8, 10
(This sequence has 5 terms – it ends at 10)
13.
Classifications of
Sequence
INFINITE SEQUENCE
Aninfinite sequence has no end- it goes on
forever. It keeps following the same rule
endlessly.
You can describe the rule, but you can’t list all
the terms.
Example: 1, 2, 4, 8, 16, …
(This sequence keeps doubling and never
stops)
Problem: Find the20th term of
5, 8, 11, 14...
Step 1: Identify a₁ = 5, d = 3
Step 2: Apply formula a₂₀ = 5 + (20-
1)×3 = 62
Step 12:
Arithmetic
Sequence
Problem
16.
Geometric
Sequences –
Definition and
Attributes
Ageometric sequence is a sequence where
each term is found by multiplying the
previous term by a constant ratio. Key
attributes include the common ratio (r) and
the first term (a₁).
Example: 2, 6, 18, 54, … (r = 3)
17.
Attributes of
Geometric
Sequences
Illustrated
General termformula: aₙ = a₁ × r(n-1)
Constant ratio between consecutive terms
Exponential growth (r > 1) or decay (0 < r < 1)
Example: For 2, 6, 18, 54... find the 5th term: a₅ = 2 × 3⁴ =
162
18.
Find the 8thterm: 3, 6, 12, 24, ...
a₁ = 3, r = 2 a₈ = 3 × 2⁷ = 384
→
Step 15:
Geometric
Sequence
Problem
Solving Real-
World Problems
withSequences
Arithmetic Example: You save $50 more
each month. Starting with $100, your
savings grow: $100, $150, $200, $250... Use
aₙ = a₁ + (n-1)d to find any month's total!
Geometric Example: Bacteria double every hour: 1, 2, 4, 8,
16...
21.
Key Takeaways
Patterns appeareverywhere in nature and art
Fibonacci is a special recursive
pattern
Arithmetic adds constant; geometric multiplies
ratio
22.
ARITHMETIC SEQUENCE |
EXAMPLES
Example1
The sequence is:
7, 12, 17, 22, ...
Find the 20th term (a20)
Given:
a₁ = 7; n = 20
d = a2 – a1
d = 12 – 7
d = 5
Formula: aₙ = a1 + (n - 1)d
Solution:
a20 = a1 + (n - 1)d
a20 = 7 + (20– 1) x 5
a20 = 7 + (19) x 5
a20 = 7 + 95
a20 = 102
23.
ARITHMETIC SEQUENCE |
EXAMPLES
Example2
Find the 30th term of the arithmetic
sequence: −15, −9, −3, 3, ...
Find: a30
Given:
a₁ = -15; n = 30
d = a2 – a1
d = -9 – -15
d = 6
Formula: aₙ = a1 + (n - 1)d
Solution:
a30 = a1 + (n - 1)d
a30 = -15 + (30– 1) x 6
a30 = -15 + (29) x 6
a30 = -15 + 174
a30 = 159
24.
ARITHMETIC SEQUENCE |
EXAMPLES
Example3
The second term of an arithmetic
sequence is 18, and the common
difference is −4.
Find the 100th
term (a100)
Given:
d = - 4; n = 35
a₁ = a2 – d
a₁ = 18 – (-4)
a₁ = 22
Formula: aₙ = a1 + (n - 1)d
Solution:
a100 = a1 + (n - 1)d
a100 = 22 + (100 – 1) x -4
a100 = 22 + (99) x -4
a100 = 22 - 396
a100 = -374
25.
ARITHMETIC SEQUENCE |
EXAMPLES
Solution:
a18= a1 + (n - 1)d
a18 = 500 + (18 – 1) x 150
a18 = 500 + (17) x 150
a18 = 500 + 2550
a18 = ₱3050
Word Problem 1 – Savings
Maria saves ₱500 during the first week. She decides to increase the amount she
saves by ₱150 every week. If this pattern continues, how much will Maria save
during the 18th
week?
Find the 18th
week savings (a18)
Given:
a₁ = ₱500 ; n = 18th
week
d = ₱150
Formula: aₙ = a1 + (n - 1)d
26.
ARITHMETIC SEQUENCE |
EXAMPLES
Solution:
a24= a1 + (n - 1)d
a24 = 25000 + (24 – 1) x 800
a24 = 25000 + (23) x 800
a24 = 25000 + 18400
a24 = ₱43400
Word Problem 2 – Salary Increase
A newly hired employee receives a monthly salary of ₱25,000 during the first
month. Every succeeding month, his salary increases by ₱800.
What will be his salary during the 24th month?
Find the 24th
month salary increase (a24)
Given:
a₁ = ₱25,000 ; n = 24th
week
d = ₱800
Formula: aₙ = a1 + (n - 1)d
27.
GEOMETRIC SEQUENCE |EXAMPLES
Example 1
Find the 12th term of the sequence:
3, 6, 12, 24, ...
Find the 12th
term (a12)
Given:
a₁ = 3
r = a2 / a1
r = 6 / 3
r = 2
n = 12
Formula: aₙ = a₁ × r(n-1)
Solution:
a12 = a₁ × r (n-1)
a12 = 3 × 2 (12-1)
a12 = 3 × 2 (11)
a12 = 3 × 2048
a100 = 6144
28.
GEOMETRIC SEQUENCE |EXAMPLES
Example 2
Determine the 15th term of the
sequence:
2, 8, 32, 128, ...
Find the 15th
term (a15)
Given:
a₁ = 2
r = a2 / a1
r = 8 / 2
r = 4
n = 15
Formula: aₙ = a₁ × r(n-1)
Solution:
a15 = a₁ × r (n-1)
a15 = 2 × 4 (15-1)
a15 = 2 × 4 (14)
a15 = 2 × 268,435,456
a15 = 536,870,912
29.
GEOMETRIC SEQUENCE |EXAMPLES
Example 3
The third term of a geometric sequence is
96, and the common ratio is ½.
Find the 10th term.
Find the 10th
term (a10)
Given:
r =
n = 10; a3 = 96
a2 = a3 / r
a2 =96 / 0.5 = 192
a1 = 192 / 0.5 = 384
Formula: aₙ = a₁ × r(n-1)
Solution:
a10 = a₁ × r (n-1)
a10 = 384 × (10-1)
a10 = 384 × (9)
a10 = 384 ×
a10 = 0.75
30.
GEOMETRIC SEQUENCE |EXAMPLES
Solution:
a8 = 10000 × 1.20 (8-1)
a8 = 10000 × 1.20 (7)
a8 = 10000 × 3.5832
a8 = ₱35,831.81
Word Problem 1 – Investment
Carlos invested ₱10,000 in a business that grows by 20% every year.
Assuming the investment grows according to a geometric sequence, what will be
its value at the 8th year?
Find the 8th
year investment value (a18)
Given:
a₁ = ₱10,000 ; n = 8th
year
r = 100%(principal amount) + 20%
r = 120% or 1.20
Formula: aₙ = a₁ × r(n-1)
31.
GEOMETRIC SEQUENCE |EXAMPLES
Solution:
a9 = 200 × 2 (9-1)
a9 = 200 × 2 (8)
a9 = 200 × 256
a9 = 51,200 bacteria
Word Problem 2 – Bacteria Growth
A laboratory culture contains 200 bacteria. Every hour, the number of bacteria
doubles. How many bacteria are present after the 9th hour?
Find: No. of bacteria present after the
9th hour (a9)
Given:
a₁ = 200 bacteria ; n = 9th
hour
r = 2 (the no. of bacteria doubles
every hour
Formula: aₙ = a₁ × r(n-1)
32.
ASSIGNMENT
1. A patienttakes 80 mg of medicine on the first day. Because of
recovery, the dosage is reduced by half every day. What will
be the dosage on the 7th day?
2. A community plants 45 trees during the first month of a
reforestation project. Each month, they plant 12 more trees
than they did the previous month. If they continue this
pattern, how many trees will they plant during the 24th
month?
Editor's Notes
#13 Example: 1, 2, 4, 8, 16, 32, …
(This keeps doubling and never stops.)
#14 Example: 1, 2, 4, 8, 16, 32, …
(This keeps doubling and never stops.)
#24 The first term of an arithmetic sequence is 18, and the common difference is −4.
Find the 35th term.
#25 The first term of an arithmetic sequence is 18, and the common difference is −4.
Find the 35th term.
#26 The first term of an arithmetic sequence is 18, and the common difference is −4.
Find the 35th term.