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Learn how to make conjectures based on patterns and use counterexamples to disprove statements. Practice identifying patterns, making conjectures, and finding counterexamples with numbers and geometric figures.
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Patterns and Inductive Reasoning Chapter 2-1
Make conjectures based on inductive reasoning. • conjecture • counterexample • Find counterexamples. Standard 1.0Students demonstrate understanding byidentifying and giving examples ofundefined terms, axioms, theorems, and inductiveand deductive reasoning. (Key) Standard 3.0Studentsconstruct and judge the validity of a logical argument and give counterexamples to disprove a statement.(Key) Lesson 1 MI/Vocab
Patterns • What is next?
×2 ×3 ×4 ×5 Patterns and Conjecture Make a conjecture about the next number based on the pattern. 2, 4, 12, 48, 240 Find a pattern: 2 4 12 48 240 The numbers are multiplied by 2, 3, 4, and 5. Conjecture: The next number will be multiplied by 6. So, it will be 6 ● 240 or 1440. Answer:1440 Lesson 1 Ex1
Describe the pattern and find the next number. • 1, 4, 16, 64… • Multiply by 4 • 256 • -5, -2, 4, 13… • Add subsequent multiples of 3. {3, 6, 9, 12…) • 25 • 5, 7, 14, 16, 32, 34… • Add 2, then multiply by 2 • 68
A.B. C.D. • A • B • C • D Lesson 1 CYP1
Conjecture • An unproven statement based on prior facts • All Football players are dumb. • All English teachers are short. • All even numbers are divisible by 2.
Counterexample A specific example that proves a conjecture is false Give a counterexample to the conjecture that: • “All months end in the letter y.” • March, April, September, etc. • “All numbers are divisible by 2.” • 3, 7, 39, etc. • “For all real numbers x, x2 x. • .5, .1, .938, etc.
Geometric Conjecture For points L, M, and N, LM = 20, MN = 6,and LN = 14.Make a conjecture and draw a figure to illustrate your conjecture. Given: points L, M, and N; LM = 20, MN = 6, and LN = 14. Examine the measures of the segments. Since LN + MN = LM, the points can be collinear with point N between points L and M. Answer: Conjecture:L, M, and N are collinear. Lesson 1 Ex2
Given: ACE is a right triangle with AC = CE. Which figure would illustrate the following conjecture? ΔACE is isosceles, C is a right angle, and is the hypotenuse. A.B. C.D. • A • B • C • D Lesson 1 CYP2
UNEMPLOYMENTBased on the table showing unemployment rates for various counties in Texas, find a counterexample for the following statement. The unemployment rate is highest in the cities with the most people. Answer: Maverick has a population of 50,436 people in its population, and it has a higher rate of unemployment than El Paso, which has 713,126 people in its population. Lesson 1 Ex3
DRIVINGBased on the table, which two states could be used as a counterexample for the following statement?The greater the population of a state, the lower the number of drivers per 1000 residents. • A • B • C • D • Texas & California • Vermont & Texas • Wisconsin & West Virginia • Alabama & West Virginia Lesson 1 CYP3
Homework Chapter 2-1 • Pg 80 1, 2, 5 – 16, 25 – 30, 33, 40, 43 – 48