So one way you could think of it, if you set f of x as being equal to sine of x, and g of x being the natural log of x, and let's see, fg, let's say h of x, h of x equaling x squared, then this thing right over here is the exact same thing as trying to take the derivative with respect to x of f of g of h of x. And what I want to do is kind of think about it how I would do it in my head, without having to write all the chain rule notation. So the way I would think about this, if I were doing this in my head, is the derivative of this outer function of f with respect to the level of composition directly below it. So the derivative of sine of x is cosine of x. But instead of it being cosine of x, it's going to be cosine of whatever was inside of here. So it's going to be cosine of natural log. Let me write that in that same color.