I would get the derivative of y with respect to x is equal to, and actually, yeah, I would get, I'm just gonna divide by two. So I'm gonna get negative x minus y and then I'm going to get plus 1 1 2. So it's not obvious to me how I can write this as a product of a function of x and a function of y. So this one does not feel, this one right over here is not separable. I don't know how to write this as a function of x times a function of y. So this one I'm gonna say is not separable. Now this one, they've already written it for us as a function of x times a function of y.