Negative x divided by two x is negative 1 1 2. Or we could say that x is equal to e to the negative 1 1 2 is equal to x. Remember, natural log is just log base e. So e to the negative 1 1 2, which we could also write like that, e to the negative 1 1 2, or one over the square root of e. So that's a point at which g, at which our derivative, I should say, is equal to zero. It is a critical point or critical value for our original function g. So, and that's the only place where g prime is equal to zero. Are there any other points where g prime is undefined? And there have to be points within the domain. So let's see, what would make this undefined?