What we're going to do in this video is introduce ourselves to the notion of a definite integral. And with indefinite integrals and derivatives, this is really one of the pillars of calculus. And as we'll see, they are all related, and we'll see that more and more in future videos, and we'll also get a better appreciation for even where the notation of a definite integral comes from. So let me draw some functions here. And we're actually gonna start thinking about areas under curves. So let me draw coordinate axes here. So that's my y-axis.