One-to-One Functions

To have an inverse, a function must be one-to-one, which means that no two elements in the domain of f  correspond to the same element in the range of f.

A function of f is one-to-one if, for a and b in its domain,
          f(a) = f(b) implies that  a = b

When testing if a function is one to one, you have to let a and b be nonnegative real numbers

                                                       2(a) + 1 = 2(b) = 1

                                                           2(a) = 2(b)

                                                               a = b