I know this is asking quite a bit, but if you have the free time, I would appreciate your help very much...

On the MIT Opencourseware site, in the single variable calculus class, the professor works a problem that goes roughly like this:

Find the area of a triangle whose sides are formed by the tangent line of a F(x)= 1/x, and the x & y axises. I have provided a link for the video below. My question is this: About the 40:55 minute mark, he comes up with the conclusion that 1/2 *2x0 (x nought)*2y0(y nought) = 2 and I dont understand how he gets 2. If someone has the free time would they mind watching and trying to explain it to me? The problem starts around the 28:15 mark. Again, I know answering this question would prob use up alot of your time, but if you are willing, I would appreciate it so much. Thanks.

MIT OpenCourseWare | Mathematics | 18.01 Single Variable Calculus, Fall 2006 | Video Lectures | Video Lectures - Lecture 1