What is that going to be equal to? Well let's see, let's just evaluate it. L of 4.36 is going to be f of four. So it's going to be two plus the derivative, so the slope of this line, plus f prime of four times x minus four. So 4.36 minus four is going to be times 0.36. And that makes sense, you're starting at two, and you're saying okay, my change in x, my change in x is 4.36, so my change in y is going to be my slope times that change in x to get me that value, to get me that value right over there. So let's figure out, let's figure out what this, let's figure out what this thing, what this thing actually is.