And how would we represent that? How would we denote that? Well, we could denote that as the definite integral between a and b of f of t, of f of t, dt. And there you have it. This right over here is the second fundamental theorem of calculus. It tells us that this, if f is continuous on the interval, that this is going to be equal to the antiderivative or an antiderivative of f. And we see right over here that capital F is the antiderivative of f. So we could view this as capital F antiderivative. This is how we define capital F. The antiderivative, or we didn't define it that way, but the fundamental theorem of calculus tells us that capital F is an antiderivative of lowercase f. So right over here, this tells you, if you have a definite integral like this, it completely equivalent to an antiderivative of it evaluated at f and from that, or evaluated at b, and from that, you subtract it, evaluated at a.