Suppose that f is an even function whose domain is the set of all real numbers. Then which of the following can we claim to be true? The function f has an inverse f –1 that is even. The function f has an inverse f –1 that is odd. The function f has an inverse f –1, but we can't tell whether it's even or odd. f –1 is not a function. We can't tell whether or not f has an inverse.