Equality
Relationship between two quantities of the same value or between two representations of the same mathematical object.
An equality can be either true, either false. It cannot be true and false at the same time. The truth or untruth property of an equality is called its truth value.
Notation
- The relationship of equality is noted using the symbol "=" which is read as "is equal to".
- This symbol can only be used between numbers, numerical variables, vectors, matrices, or sets.
- 7 = 5 + 2 is a true equality, but 17 = 1 + 7 is a false equality.
Example
- The relationship 12 + 21 = 33 is read as "twelve plus twenty-one is equal to thirty-three".
- E = {1, 2, 3} means that the letter E represents the set containing the elements 1, 2, and 3.
- ℜ = {(1, 2), (3, 4), (7, 6)} means that the letter ℜ is used here to represent the relationship (or the set) containing the ordered pairs (1, 2), (3, 4), and (7, 6).