1.1 patterns and inductive reasoning - weebly
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1.1 Patterns and Inductive Reasoning
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December 7, 2015
Ms. EngbrechtGeometry A2015 2016
About Me
Student Survey Textbooks*COVER YOUR BOOK
Bring In PAPER BAG if you need help
WHEN YOU GET BACK, WORK ON YOUR SURVEY
Syllabus&
Hall Passes
RESPECT• Yourself• Others• Property
1.1 Patterns and Inductive Reasoning
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December 7, 2015
No food or beverage (except water)
No electronics except your calculator
(No Phone, iPod, iPad, etc.)
Be on time (In your seat when bell rings)
Have a good attitude
Follow the rules set forth by the school
GRADES50% tests
30% quizzes
20% assignments
Expect it daily
Typically due at the Beginning of next class
Testing Procedure Review Day
Test Day
Correction Day
Outside of class Retake if you have all assignments done
My Pet Peeves passes (only during work time)
end of the hour (stay in your seat)
sharpening pencils (do it before class or during work time)
be prepared (notes, book, pencil and paper)
NO PHONE (if I see it, I will take it)
ASK FOR HELP WHEN NEEDED*Directed Study
*Before School (most days)
*After School
1.1 Patterns and Inductive Reasoning
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December 7, 2015
Any Questions? WarmUp Evaluate the following expressions:
1) 9 17
2) 5 3
3) (2) + 4
4) (0.5) + 0
5)
2 2
2 2
14
6) 22 5
7) (x + 1)2
for x = 2
Natural #'s 1,2,3...
Whole #'s 0,1,2,3...
Integers ...2,1,0,1,2...
Rational #'s ...1/2, 0.222, 0, 4/5, 1.58
Real Numbers
Irrational #'s
2 ,
Goals:
1.1 Patterns and Inductive Reasoning
To find and describe patterns
To use inductive reasoning to make conjectures
Essential Question:What is a conjecture and how can we prove one is false?
conjecture: an educated guess that is believed to be true, but is not yet proven
Ex:
inductive reasoning: a process that includes looking for patterns and making conjectures
VocabularyCounterexample an example that shows a
conjecture is false
*only need 1 counterexample to prove a conjecture false
*to prove conjecture is true, need to prove it true for all cases
*conjectures that are not known to be true or false are called unproven or undecided
1.1 Patterns and Inductive Reasoning
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Sketch the next figure in the pattern.
Example 1: Describing a Visual Pattern Try It1. Sketch the next figure in the pattern
Example 2: Describing a Number PatternDescribe a pattern in the sequence of numbers. Predict the next number.
a) 128, 64, 32, 16, ... b) 5, 4, 2, 1, ...
Try ItDescribe the number pattern in the sequence of numbers. Predict the next number.
2.) 4, 20, 100, 500, ...
3.) 10, 20, 40, 70, 110, ...
Example 3: Making a Conjecture
Conjecture: The sum of the first n even positive integers is ___.?Soln: List some specific examples and look for a pattern.Examples:
first even integer:
sum of first two even positive integers:
sum of first three even positive integers:
sum of first four even positive integers:
2 = 1(__)
2 + 4 = __ = 2(__)
2 + 4 + 6 = ___ = 3(__)
2 + 4 + 6 + 8 = ___ = 4(__)
Conjecture:
Complete the conjecture. Show the conjecture is false by finding a counterexample
Conjecture: If the difference of two numbers is odd, then the greater of the two numbers must also be odd.
Hint: Write a difference so that the greater of the two numbers is even.
Example 4: Finding a Counterexample
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Complete the conjecture based on the pattern you observe.
1 = 11 + 2 = 3 =
2(2+1)2
1 + 2 + 3 = 6 = 3(3+1)2
1 + 2 + 3 + 4 = 10 = 4(4+1)2
5(5+1)2
6(6+1)2
1 + 2 + 3 + 4 + 5 = 15 =
1 + 2 + 3 + 4 + 5 + 6 = 21 =
Conjecture: The sum of the first n positive integers
is.
Try It 4.) Try itShow the conjecture is false by finding a counterexample.
Conjecture: The difference of two negative numbers is always negative.
5.)
Complete the conjecture based on the pattern you observe.
Conjecture: The sum of the first n odd positive integers is ____.?
1 = 1
1 + 3 = 4 = 2
1 + 3 + 5 = 9 = 3
1 + 3 + 5 + 7 = 16 = 4
2
2
2
2
Conjecture: The sum of the first n odd positive integers is ____.
Exit Slip SummaryWhat is a conjecture and how can we prove one is false?
EQ:
1.1 HW p.6 #1226even, 27, 2844even, 47, 48, 6070even
Name
Hr.__(first & last)
12)
14)
*Go DOWN the pg
*SKIP a line between problems
*Write the original problem
*SHOW YOUR WORK*Get Syllabus Signed
*Cover Your Book
1.1 Homeworkpg. 6 #1226 even, 27, 2846 even, 47, 48, 5270 even
*Get Syllabus Signed
*Cover Your Book
*Put section # at top of HW
*Skip a line between problems