Page 180 - Math Course 2 (Book 2)
P. 180

Conditional Statements




                                                            inverse
          MO. 12 - L3b
                                                            negating both the hypothesis and conclusion of
                                                            the conditional.
                 Related Conditionals

                                                                           If a number is even, then it is
                                                            Conditional:
                                                                           divisible by 2.
                                                                           If a number is divisible by 2, then
                                                            Converse:
                     Vocabulary A-Z                                        it is even.
                     Let us learn some vocabulary           Inverse:       If a number is not even, then it is
                                                                           not divisible by 2.

                                                                           If a number is not divisible by 2,
         related conditionals                               Contrapositive:  then it is not even.
         Other statements based on a given conditional
         statement are known as related conditionals.       contrapositive
         They are in the form of converse, inverse and      negating both the hypothesis and conclusion of
         contrapositive.
                                                            the converse statement.

                        If a number is even, then it is
         Conditional:                                                      If a number is even, then it is
                        divisible by 2.                     Conditional:   divisible by 2.
                        If a number is divisible by 2, then
         Converse:                                                         If a number is divisible by 2, then
                        it is even.                         Converse:      it is even.
                        If a number is not even, then it is
         Inverse:                                                          If a number is not even, then it is
                        not divisible by 2.                 Inverse:       not divisible by 2.
                        If a number is not divisible by 2,
         Contrapositive:                                                   If a number is not divisible by 2,
                        then it is not even.                Contrapositive:
                                                                           then it is not even.
         converse
         exchanging the hypothesis and conclusion of the    logically equivalent
         conditional.                                       Statements with the same truth values are said to
                                                            be logically equivalent.
                        If a number is even, then it is
         Conditional:
                        divisible by 2.                      A conditional and its contrapositive are logically
                                                             equivalent. The converse and inverse of a condi-
                        If a number is divisible by 2, then
         Converse:                                           tional are logically equivalent. These relationship
                        it is even.                                  are summarized in the table.
                        If a number is not even, then it is
         Inverse:                                                    Conditional  Converse   Inverse   Contrapositive
                        not divisible by 2.                  p   q     p –> q   q –> p  ~p –> ~q  ~p –> ~q
                        If a number is not divisible by 2,   T   T      T         T       T         T
         Contrapositive:
                        then it is not even.                 T   F      F         T       T         F

         Key Concept                                         F   T      T         F       F         T
                                                                                                    T
                                                                                  T
                                                                                          T
                                                                        T
                                                                 F
                                                             F
         Related Conditionals

           Statement               Formed by               Symbols                 Examples

                                                                       If two angles have the same measure,
          Conditional     given hypothesis and conclusion    p → q
                                                                             then they are congruent.

           Converse       exchanging the hypothesis and      q → p     If two angles are congruent, then they
                           conclusion of the conditional
                                                                             have the same measure.
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