True or false on relations and functions

Exercise and reference answers

Questions

1. Statement is true

   Yes

   Statement

   A relation in A is a subset of A x A.

2. Statement is true

   No

   Statement

   The universal relation leaves out some pairs.

3. Statement is true

   Yes

   Statement

   Every triangle is congruent to itself.

4. Statement is true

   No

   Statement

   A line can be perpendicular to itself.

5. Statement is true

   Yes

   Statement

   Injective is another word for one-one.

6. Statement is true

   No

   Statement

   An invertible function may fail to be onto.

Instructions

Decide whether each statement is true or false.

Explanation