1. Inverse, Contrapositive & indirect proofs Sections 6.2/6.3

2. Converse Switches hypotheses and conclusion. Statement: if this is silly then it is useless. Converse: if this is useless then it is silly.

3. Inverse Negates hypotheses and conclusion. Statement: if this is silly then it is useless. Converse: if this is not silly then it is not useless.

4. Contrapositive Negates and switches hypotheses and conclusion. Statement: if this is silly then it is useless. Converse: if this is not useless then it is not silly.

5. Logically equivalent Two statements that are always both true or both false. A Statement and the contrapositive are logically equivalent. The inverse and converse of a statement are logically equivalent

6. Indirect Proofs Assume temporarily that conclusion is not true. Reason logically until you reach a contradiction of a known fact