I'm making these little squares to show what you do with the input. And then what do you produce? Well, you produce the natural log of the square root of x. Natural log of the square root of x, which is equal to f of x. So you could view f of x as this entire, as this entire set, or this entire, I guess you could say, this combination of functions right over there. And that is f of x, which is essentially a composition of two functions. You're inputting into one function, then taking that output and inputting it into another.