And then we can take the derivative of both sides of this with respect to time to get a relationship between all the things that we care about. So what's the derivative of x squared with respect to time? Well, it's going to be the derivative of x squared with respect to x, which is just 2x, times the derivative of x with respect to time, times dx dt. Once again, just a chain rule. Derivative of something squared with respect to the something times the derivative of the something with respect to time. And we use similar logic right over here when we want to take the derivative of y squared with respect to time. Derivative of y squared with respect to y times the derivative of y with respect to time.