You could say y is equal to the positive square root of one minus x squared. And you could say y is equal to the negative square root of one minus x squared. Take the derivatives of each of these separately, and you would be able to find the derivative for any x, or the derivative of the slope of the tangent line at any point. But what I wanna do in this video is literally leverage the chain rule to take the derivative implicitly so that I don't have to explicitly define y as a function of x either way. And the way we do that is literally just apply the derivative operator to both sides of this equation and then apply what we know about the chain rule. Because we are not explicitly defining y as a function of x and explicitly getting y is equal to f prime of x, they call this, which is really just an application of the chain rule, we call it implicit differentiation. Implicit differentiation.