And if I put the bracket on the right-hand side instead of a parenthesis, that means that we are including the point b. And continuous just means we don't have any gaps or jumps in the function over this closed interval. Now let's also assume that it's differentiable over the open interval between a and b. So now we're saying, well, it's okay if it's not differentiable right at a, or if it's not differentiable right at b. And differentiable just means that there's a defined derivative, that you can actually take the derivative at those points. So it's differentiable over the open interval between a and b. So those are the constraints we're gonna put on ourselves for the mean value theorem.