So let's imagine some other x value. This right over here is the point x, well, we could say f of x or we could even say the natural log of x. What is the slope of the secant line between those two points? Well, it's going to be your change in y values, so it's going to be natural log of x minus 1 over your change in x values. That's x minus e. So that's the slope of the secant line between those two points. Well, what if you want to get the tangent line? Well, let's just take the limit as x approaches e. As x gets closer and closer and closer, these points are going to get closer and closer and closer, and the secant line is going to better approximate the tangent line.