1 / 17

Conditional Statements: Definition, Symbolic Logic, and Forms

This lesson covers the definition of conditional statements, their symbolic logic representation, and different forms such as converse, inverse, contrapositive, and biconditional.

jstlouis
Download Presentation

Conditional Statements: Definition, Symbolic Logic, and Forms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Conditional Statements Lesson 2-1 Lesson 2-1 Conditional Statements

  2. Conditional Statement Definition: A conditional statement is a statement that can be written in if-then form. “If _____________, then ______________.” Example: Ifyour feet smell and your nose runs, then you're built upside down. Continued…… Lesson 2-1 Conditional Statements

  3. Conditional Statement - continued Conditional Statements have two parts: The hypothesis is the part of a conditional statement that follows “if” (when written in if-then form.) The hypothesis is the given information, or the condition. The conclusionis the part of an if-then statement that follows “then” (when written in if-then form.) The conclusion is the result of the given information. Lesson 2-1 Conditional Statements

  4. Conditional statements can be written in “if-then” form to emphasize which part is the hypothesis and which is the conclusion. Writing Conditional Statements Hint: Turn the subject into the hypothesis. Example 1: Vertical angles are congruent. can be written as... Conditional Statement: If two angles are vertical, then they are congruent. Example 2: Seals swim. can be written as... Conditional Statement: If an animal is a seal, then it swims. Lesson 2-1 Conditional Statements

  5. If …Then vs. Implies Two angles are verticalimplies they are congruent. Another way of writing an if-then statement is using the word implies. If two angles are vertical, then they are congruent. Lesson 2-1 Conditional Statements

  6. Conditional Statements can be true or false: • A conditional statement is false only when the hypothesis is true, but the conclusion is false. • A counterexample is an example used to show that a statement is not always true and therefore false. Statement: If you live in Virginia, then you live in Richmond. Yes !!! Is there a counterexample? Counterexample: I live in Virginia, BUT I live in Glen Allen. Therefore () the statement is false. Lesson 2-1 Conditional Statements

  7. Symbolic Logic • Symbols can be used to modify or connect statements. • Symbols for Hypothesis and Conclusion: Hypothesis is represented by “p”. Conclusion is represented by “q”. if p, then q or p implies q Continued….. Lesson 2-1 Conditional Statements

  8. Symbolic Logic - continued if p, then q or p implies q p  q is used to represent Example: p: a number is prime q: a number has exactly two divisors pq: If a number is prime, then it has exactly two divisors. Continued….. Lesson 2-1 Conditional Statements

  9. is used to represent the word Symbolic Logic - continued ~ “not” Example 1: p: the angle is obtuse ~p: The angle is not obtuse Note: ~p means that the angle could be acute, right, or straight. Example 2: p: I am not happy ~p: I am happy ~p took the “not” out- it would have been a double negative (not not) Lesson 2-1 Conditional Statements

  10. is used to represent the word Symbolic Logic - continued  “and” p:a number is even q: a number is divisible by 3 Example: A number is even and it is divisible by 3. i.e. 6,12,18,24,30,36,42... pq: Lesson 2-1 Conditional Statements

  11. is used to represent the word Symbolic Logic-continued  “or” p: a number is even q: a number is divisible by 3 Example: pq: A number is even or it is divisible by 3. i.e.2,3,4,6,8,9,10,12,14,15,... Lesson 2-1 Conditional Statements

  12. is used to represent the word Symbolic Logic - continued  “therefore” Example: Therefore, the statement is false.  the statement is false Lesson 2-1 Conditional Statements

  13. Forms of Conditional Statements Converse: Switch the hypothesis and conclusion (q  p) pqIftwo angles are vertical, thenthey are congruent. qpIftwo angles are congruent, thenthey are vertical. Continued….. Lesson 2-1 Conditional Statements

  14. Forms of Conditional Statements Inverse:State the opposite of both the hypothesis and conclusion. (~p~q) pq :Iftwo angles are vertical, thenthey are congruent. ~p~q:Iftwo angles are not vertical, thenthey are not congruent. Lesson 2-1 Conditional Statements

  15. Forms of Conditional Statements Contrapositive: Switch the hypothesis and conclusion and state their opposites. (~q~p) pq : Iftwo angles are vertical, thenthey are congruent. ~q~p:Iftwo angles are not congruent, thenthey are not vertical. Lesson 2-1 Conditional Statements

  16. Forms of Conditional Statements • Contrapositives are logically equivalent to the original conditional statement. • If pq is true, then qp is true. • If pq is false, then qp is false. Lesson 2-1 Conditional Statements

  17. Biconditional • When a conditional statement and its converse are both true, the two statements may be combined. • Use the phrase if and only if (sometimes abbreviated: iff) Statement: If an angle is right then it has a measure of 90. Converse:If an angle measures 90, then it is a right angle. Biconditional:An angle is right if and only if it measures 90. Lesson 2-1 Conditional Statements

More Related