Question

Which of the following statements isn't true regarding functions?

A. The horizontal test may be used to determine whether a function is one-to-one
B. A sequence is a function who's domain is the set of natural numbers.
C. A function is a relation in which each value of the input variable is paired with at least one value of the output value.
D. The vertical line test may be used to determine whether a function is one-to-one.