Question 637552
I'm not a wizard on this topic, but I think one to one means that for each value of x there is a unique value of f(x) or g(x). If so these are true functions, because for every real value of x you get a single value for f(x) or g(x). The ln bothered me, but the argument x^2 + 1 is always positive, thus ln(positive number) exists and unique (single valued). An example of a non one to one is f(x) = sqrt(x). If x=4, f(4) = + or - 2, two different values satisfy the f(x), thus not unique. These functions, especially g(x), may not hold for complex values of x.