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Inductive and Deductive Reasoning. Vocabulary. A conjecture is an unproven statement that is based on observations. You use inductive reasoning when you find a pattern in specific cases and then write a conjecture for the general case. Write a conjecture.
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Vocabulary A conjecture is an unproven statement that is based on observations. You use inductive reasoning when you find a pattern in specific cases and then write a conjecture for the general case.
Write a conjecture • Look at the patterns below and write a conjecture for the next number in the sequence.
Vocabulary • A counterexample is a specific case for which the conjecture is false.
Counterexample Find a counter example to show that the following conjecture is false. The sum of two numbers is always greater than the larger number.
Vocabulary A conditional statement is logical statement that has two parts, a hypothesis and a conclusion. The hypothesis is the “if” part of the conditional statement. The conclusion is the “then” part of the conditional statement.
Writing a conditional statement: The hypothesis tells you what you are talking about, and the conclusion describes the hypothesis.
Writing a conditional statement • Writing the following statements in if-then form. 1. Two angles that make a linear pair are supplementary. 2. All 90o angles are right angles.
Vocabulary • The negation of a statement is the opposite of the original.
Negation • Negate the following statements. 1. The ball is red. 2. The cat is not black.
Vocabulary • The inverse of a conditional statement negates the hypothesis and conclusion • The converse of a conditional statement switches the hypothesis and conclusion. • The contrapositive of a conditional statement takes the inverse of the converse.
Writing statements • Write the inverse, converse, and contrapositive of the conditional statement: “If two angles form a linear pair, then they are supplementary.” Which statements are always true?
Vocabulary • If a conditional statement and its converse are both true, then we can write it as a biconditional statement by using the phrase if and only if instead of putting it in if-then form. 1. If an angle has 90˚, then it is a right angle.
Conclusion • Explain how to write a conditional statement, its inverse, converse, and contrapositive.
Assignment Pg. 75 #5-17 odd Pg. 82 #4-14 even, 19, 21