This is the equation of our curve. And we know that dy dx is equal to y over three y squared minus x. So one thing that we could do is, well, let's just figure out what the derivative of x with respect to y is and set that to be equal to zero. So this is the derivative of y with respect to x. If we take the reciprocal of that, the derivative of x with respect to y, just the reciprocal of this, is going to be the reciprocal of what we have here. So it's going to be three y squared minus x over y. And if we want this to be equal to zero, like we said right over here, well, then that's only going to happen if the numerator is equal to zero.