Inverse Functions, Logarithms, and Definition of 'e' - Lecture 19 (Calculus 1)

A function f is one-to-one provided:

1. A.Every input has exactly one output
2. B.Whenever f(a) = f(b), it must follow that a = b
3. C.Its graph passes the vertical line test
4. D.It has at least one fixed point on its domain