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Patterns and Growth. John Hutchinson. Problem 1: How many handshakes?. Several people are in a room. Each person in the room shakes hands with every other person in the room. How many handshakes take place?. Is there a pattern?. Here’s one. Here’s another. What is:.
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Patterns and Growth John Hutchinson TM MATH: Patterns & Growth
Problem 1: How many handshakes? Several people are in a room. Each person in the room shakes hands with every other person in the room. How many handshakes take place? TM MATH: Patterns & Growth
Is there a pattern? TM MATH: Patterns & Growth
Here’s one. TM MATH: Patterns & Growth
Here’s another. TM MATH: Patterns & Growth
What is: 1 + 2 + 3 + 4 + …..+ 98 + 99 + 100? TM MATH: Patterns & Growth
Look at: There are 100 different 101s. Each number is counted twice. The sum is (100*101)/2 = 5050. TM MATH: Patterns & Growth
Look at: 1 + 2 + 3 + 4 + 5 + 6 = 3 7 = 21 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 = 4 7 = 28 TM MATH: Patterns & Growth
If there are n people in a room the number of handshakes is n(n-1)/2. TM MATH: Patterns & Growth
Problem 2: How many intersections? Given several straight lines. In how many ways can they intersect? TM MATH: Patterns & Growth
2 Lines 1 0 TM MATH: Patterns & Growth
3 Lines 0 intersections 1 intersection 2 intersections 3 intersections TM MATH: Patterns & Growth
Problem 2A Given several different straight lines. What is the maximum number of intersections? TM MATH: Patterns & Growth
Is the pattern familiar? TM MATH: Patterns & Growth
Problem 2B Up to the maximum, are all intersections possible? TM MATH: Patterns & Growth
What about four lines? TM MATH: Patterns & Growth
What about two intersections? TM MATH: Patterns & Growth
What about two intersections? Need three dimensions. TM MATH: Patterns & Growth
Problem 3 What is the pattern? 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89,… TM MATH: Patterns & Growth
Note • 1 + 1 = 2 • 1 + 2 = 3 • 2 + 3 = 5 • 3 + 5 = 8 • 5 + 8 = 13 • 8 + 13 = 21 • 13 + 21 = 43 TM MATH: Patterns & Growth
This is the Fibonacci Sequence. Fn+2 = Fn+1 + Fn TM MATH: Patterns & Growth
Divisibility • Every 3rd Fibonacci number is divisible by 2. • Every 4th Fibonacci number is divisible by 3. • Every 5th Fibonacci number is divisible by 5. • Every 6th Fibonacci number is divisible by 8. • Every 7th Fibonacci number is divisible by 13. • Every 8th Fibonacci number is divisible by 21. TM MATH: Patterns & Growth
Sums of squares TM MATH: Patterns & Growth
Pascal’s Triangle TM MATH: Patterns & Growth
=32 TM MATH: Patterns & Growth
Note 1 1 2 3 5 8 TM MATH: Patterns & Growth
Problem 3A: How many rabbits? Suppose that each pair of rabbits produces a new pair of rabbits each month. Suppose each new pair of rabbits begins to reproduce two months after its birth. If you start with one adult pair of rabbits at month one how many pairs do you have in month 2, month 3, month 4? TM MATH: Patterns & Growth
Let’s count them. TM MATH: Patterns & Growth
Problem 3B: How many ways? A token machine dispenses 25-cent tokens. The machine only accepts quarters and half-dollars. How many ways can a person purchase 1 token, 2 tokens, 3 tokens? TM MATH: Patterns & Growth
Lets count them. Q = quarter, H = half-dollar TM MATH: Patterns & Growth
Observe 5 2 3 C D E F G A B C 8 13 TM MATH: Patterns & Growth
C 264 A 440 E 330 C 528 264/440 = 3/5 330/528 = 5/8 Observe TM MATH: Patterns & Growth
Note 89 55 144 89 TM MATH: Patterns & Growth
Flowers TM MATH: Patterns & Growth
References TM MATH: Patterns & Growth