Difference between revisions of "Contrapositive"

 
 
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A [[conditional]] statement is usually expressed as
 
A [[conditional]] statement is usually expressed as
  
If '''P''', then '''Q'''
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If '''P''', then '''Q'''.
  
 
The contrapositive statement is usually expressed as
 
The contrapositive statement is usually expressed as
  
If not '''Q''', then not '''P'''
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If not '''Q''', then not '''P'''.
  
 
where '''P''' denotes a condition and '''Q''' denotes another condition.
 
where '''P''' denotes a condition and '''Q''' denotes another condition.
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== Examples ==
 
== Examples ==
  
Given the conditional statement "If a polygon has 3 sides, then it is a triangle", the contrapositive is "If a polygon is not a triangle, then it does not have 3 sides".
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Given the conditional statement "If a polygon has 3 sides, then it is a triangle", the contrapositive is "If a polygon is not a triangle, then it does not have [https://artofproblemsolving.com/wiki/index.php/TOTO_SLOT_:_SITUS_TOTO_SLOT_MAXWIN_TERBAIK_DAN_TERPERCAYA TOTO SLOT] 3 sides".
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== See also ==
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* [[Logic]]

Latest revision as of 16:59, 19 February 2024

A contrapositive of a statement is always true, assuming that the conditional statement is true. However, if the conditional statement is false, then the contrapositive is also false.

A conditional statement is usually expressed as

If P, then Q.

The contrapositive statement is usually expressed as

If not Q, then not P.

where P denotes a condition and Q denotes another condition.

Examples

Given the conditional statement "If a polygon has 3 sides, then it is a triangle", the contrapositive is "If a polygon is not a triangle, then it does not have TOTO SLOT 3 sides".

See also