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Geometry. Vocabulary. Conjecture- an unproven statement that is based on observation. Inductive Reasoning- when you find a pattern in specific cases and then write a conjecture for the general case. Deductive Reasoning- Uses facts, definitions, and /or accepted properties
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Vocabulary Conjecture- an unproven statement that is based on observation. Inductive Reasoning- when you find a pattern in specific cases and then write a conjecture for the general case. Deductive Reasoning- Uses facts, definitions, and /or accepted properties Counter example- a specific case for which a conjecture is false.
Make and test a conjecture about the product of any two odd integers. Step 1: find a pattern using a few groups of small numbers
3 x 13 = 39 7 x 21 = 147 5 x 9 = 45 11 x 9 = 99 Conjecture:
Step 2: Test your conjecture using other numbers. For example, test that it works with pairs 17, 19, and 23, 31.
Make and test a conjecture about the product of any two even numbers.
Make and test a conjecture about the sum of an even integer and an odd integer
Find a counterexample to show that the conjecture is false. Conjecture: All odd numbers are prime. Solution: To find a counterexample, you need to find an odd number that is a composite number.
Find a counterexample to show that the conjecture is false. Conjecture: The difference of two positive numbers is always positive.
Conditional Statement- a logical statement that has two parts, a hypothesis ( the if part) and a conclusion ( the then part). p → q Example: If today is Tuesday, then tomorrow is Wednesday. If it is 12:01 pm, then I am hungry.
Converse- formed by switching the hypothesis and the conclusion. q → p If tomorrow is Wednesday, then today is Tuesday.
Negation- the opposite of the original statement. ~ • Inverse- Negates both the hypothesis and the conclusion. ~p → ~q • If today is not Tuesday, then tomorrow is not Wednesday.
Contrapositive- Switch the hypothesis and conclusion and negate both of them. If tomorrow is not Wednesday, then today is not Tuesday. ~q →~p
Equivalent statements- Two statements that are both true or both false. ****A conditional and its contrapositive are equivalent statement.******** Perpendicular lines- Two lines that intersect to form a right angle.
Biconditional statement- A statement that contains the phrase “if and only if”. • Today is Tuesday if and only if tomorrow is Wednesday. • Tomorrow is Wednesday if and only if today is Tuesday. • Red book page 224-2