I am not certain of your usage of ->, but I have a technique you can use that will work always.
Construct a truth table, such as this:
http://www.gateways2learning.com/SetTheory/EquivalentStatements.pdf
Which is logically equivalent to ~p -> q?
a.) ~q -> p
b.) ~q -> ~p
c.) q -> p
d.) q -> ~p
2 answers
It is just like your previous post. The contrapositive of
~p -> q
reverses the direction of implication, and the logical values:
~(q) -> ~(~p)
~q -> p
~p -> q
reverses the direction of implication, and the logical values:
~(q) -> ~(~p)
~q -> p