And we just say c is some constant between x and x squared. Well, how can we denote this area in purple? Well, that's going to be, so this thing is going to be equal to the sum of these two areas. The purple area we can show is the definite integral from x to c of our function of t. Cosine t over t dt. And then to that, we're going to add the green area. And then we'll get the original area. So the green area, for the green area, our lower bound of integration is now our constant c. And our upper bound of integration is x squared.