Chapter 1.2, Problem 8E

Express these system specifications using the propositionsp:“The user a valid password,”q:“Access is granted,” andr:“The user has paid the subscription fee" and logical connectives (including negations).

a) "The user has paid the subscription fee, but does not enter a valid password.”

b) "Access is granted whenever the user has paid the subscription fee and enters a valid password.”

c) "Access is denied if the user has not paid the subscription fee."

d) "If the user has not entered a valid password but has paid the subscription fee, then access is granted."