1. The problem statement, all variables and given/known data ((p_r)^(q_r))<-->((p^q)_r) Prove whether the following statement is a tautology , contigency or contradiction using a truth table. 2. Relevant equations 3. The attempt at a solution I did the truth table, but this whole thing is one statement no? What do I compare? the first half of the bi conditional statement to the second? or the whole statement vs. the two halves? I don't know which to compare to decide whether or not it is a contingency. EDIT: figured out the tautology is if L.H.S of <--> is equal to RHS. Sorry for the post!