And to do it, we're going to express these functions as functions of y. So our purple function, y is equal to square root of x. If we square both sides, we would get y squared is equal to x. Let me swap the sides so it makes it clear that now x is a function of y. x is equal to y squared. That's our top function, the way we've drawn it, the kind of outer shell for our figure. And then y is equal to x squared. If you take the principal root of both sides of that, it all works out because we're operating in the first quadrant here.