Multiple Choice: Click on the correct answer and the page will jump forward to the next problem.

1. If a truth table shows that a sentence is true on some rows but false on others, then
a. that sentence is not logically equivalent to any sentence. b. that sentence is logically equivalent to all sentences. c. that sentence is not logically equivalent to any logical truth. d. this tells us nothing about logical equivalence.

2. If the truth table for a pair of sentences shows they are logically equivalent, then
a. it shows that both sentences are logically true or logically false. b. it shows that both sentences are true on every row of the truth table. c. it shows that there is no row making both sentences false. d. none of the above

3. Suppose that only on the first row do the truth values of a pair of sentences differ. Then
a. those sentences cannot both be logically true. b. those sentences cannot both be logically false. c. those sentences cannot be logically equivalent. d. all of the above.