How do you decide whether the relation #sqrt(x+40)# defines a function?

1 Answer
Dec 21, 2017

A "function" is any description of related values.

Explanation:

A "function" is any description of related values. The expression given is missing the implied "is equal to..." e.g. #y = sqrt(x + 40)#, but it may be considered a "function" just as well. If defines a relationship of values, of which one is variable.

It may or may not be continuous over all real numbers, but that does not define whether it is a function or not.