On this curve, when x is equal to negative one, f of negative one is negative, is negative one half, which sticks us right over there. Let me do this in a better color. So it's right over there. And what we want to do is approximate it with a line around that. And what we're essentially going to do is we're going to approximate it with the equation of the tangent line. The tangent line is going to look something, something like that. And as we can see, as we get further and further from x equals negative one, the approximation gets worse and worse.