Question:
Using contrapositive method prove that if n2 is an even integer, then n is also an even integers.
Solution:
Let us assume
p: n2 is an even integer.
~p: n is not an even integer
q: n is also an even integer
~q=n is not an even integer.
Since, in the contrapositive, a conditional statement is logically equivalent to its contrapositive.
Therefore,
~q → ~p = If n is not an even integer then n2 is not an even integer.
Hence, ~q is true → ~p is true.
Objective type questions: