Look at the following problems: 1. Prove by falsification: a. ((p)(rq))((r)((p)q)) b. (p(rq))(pq)r 2. Define the meaning of declarative sentences and give some exan 3. Decide whether the following are declarative sentences or not: a. All cows are brown. b. The Earth is further from the sun than Venus c. There is life on Mars. d. 22=5. e. x+2=2x f. Do you want to go to the movies? g. This sentence is false