In middle school, you learned that positive and negative integers have opposite signs. In science, you learned that up and down are opposite directions. With conditional statements, sometimes the opposite of a hypothesis and conclusion happens. Those statements are called the inverse of a conditional statement.
Navigators and pilots will often respond “negative” over the radio to answer a question, “no.” You have seen this in movies and television shows. Using the word “negative” in this sense indicates an opposite response. In Geometry, we call that opposite response negation.
Definition: The negation of a statement is stating the opposite meaning of the original statement.
The negation of a true statement is false, and the negation of a false statement is true.
Examples:
Click on the blanks to check your answer.
Statement: Texas is the Lone Star State. (This is the true statement.)
Negation: Texas is Interactive button. Assistance may be required.
____
NOT
the Lone Star State.(This is the false statement)
Statement: Paris is not in Texas.
Negation: Paris Interactive button. Assistance may be required.
____
is
in Texas.
The inverse of a conditional statement is when both the hypothesis and conclusion are negated; the “If” part or p is negated and the “then” part or q is negated.
Examples:
Conditional statement: | If three points lie on a line, | then the three points are collinear |
Hypothesis / p |
Conclusion / q |
Inverse statement: | If three points DO NOT lie on a line, | then the three points are NOT collinear |
Hypothesis / p |
Conclusion / q |
Fill in the blanks.
Conditional statement: If the sun is shining, then it is not raining.