More on Conditionals

Objectives:
  • Write the converse, inverse, and contrapositive of a given conditional statement.
  • Determine the premise and conclusion of a given conditional statement.
  • Rewrite a given conditional statement in standard “if . . ., then . . . form.
  • Rewrite a biconditional as the conjunction of two conditionals.
  • Determine if two statements are equivalent using truth tables.
  • Write an equivalent variation of a given conditional.



Vocabulary:
  • converse
  • inverse
  • contrapositive
  • only if
  • biconditional
Name  Symbolic form Read as . . .
a (given) conditional p implies q
                              
the converse (of p implies q)


the inverse (of p implies q)


the contrapositive (of p implies q)




Possible Classroom Examples:

p: I am a multimillion-dollar lottery winner.
q: I am a world traveler.

p implies q
q implies p
not p implies not 1
not q implies not p

If you do not eat meat, you are a vegetarian.
You do not win, if you do not buy a lottery ticket.
I eat raw fish only if I am in a Japanese restaurant.
We eat at Burger World if and only if Ju Ju’s Kitsch-Inn is closed.

If I do not have health insurance, I cannot have surgery.

If I can have surgery, then I do have health insurance.
1.  If Proposition III passes, freeways are improved.
2. 
If Proposition III is defeated, freeways are not improved.
3. 
If the freeways are not improved, then Proposition III does not pass.
4. 
If the freeways are improved, Proposition III passes.

Truth Tables that you can use:

p:
q:

symbolic form:
p
q
 
 
 
 
 
 
 
 










































p:
q:

symbolic form:
p
q
 
 
 
 
 
 
 
 










































p:
q:

symbolic form:
p
q
 
 
 
 
 
 
 
 










































p:
q:

symbolic form:
p
q
 
 
 
 
 
 
 
 










































© 2007 Elizabeth E. K. Jones and the ASU Department of Mathematics and Statistics - All rights reserved.