sage: latex(solve (temp,diff(y)))

Unless you're referring to the D[0](y)(x) with the (x) part? But remember, you defined y to be a function of x. So solving for diff(y) will still solve for it in this sense. You can't (in Sage) ask for the "type" of a symbolic function to change like that. At least, I think that might be what you are referring to?