**Test Yourself**

Page 73

1. An _and_ statement is true when, and only when, both components are _______.

**Solution**

True.

2. An _or_ statement is false when, and only when, both components are _______.

**Solution**

False.

3. Two statement forms are logically equivalent when, and only when, they always
   have _______.

**Solution**

The same truth values.

4. De Morgan's laws says (1) that the negation of an _and_ statement is
   logically equivalent to the _______ statement in which each component is
   _______, and (2) that the negation of an _or_ statement is logically
   equivalent to the _______ statement in which each component is _______.

**Solution**

or; negated; and; negated.

5. A tautology is a statement that is always _______.

**Solution**

true

6. A contradiction is a statement that is always _______.

**Solution**

false