Which of the following are functions?
1. f(x) = 2 if x > 1 otherwise f(x) = -1
2. f(x) = 5 if x > 0 or f(x) = -5 if x < 0 or f(x) = 5 or -5 if x = 0
3. f(x) = x/10
To understand the definition of a function f, we only need to guarantee that for each x in the domain, f(x) is unique.
Based on this rule, we can do the following ...
This shows how to determine if given statements are functions.