And then we use that linearization, that linearization to find, to approximate values local to it. And this technique is called local linearization. So what I'm saying is let's figure out what this equation of this line is. Let's call that L of x. And then we can use that to, then we can evaluate that at 4.36. And hopefully that'll be a little bit easier to do than to try to figure out this right over here. So how would we do that?