Let's say that we're given the equation that y squared minus x squared is equal to four. And our goal is to find the second derivative of y with respect to x. And we wanna find an expression for it in terms of x's and y's. So pause this video and see if you can work through this. All right, now let's do it together. Now some of you might have wanted to solve for y and then use some traditional techniques. But here we have a y squared, and so it might involve a plus or minus square root.