How could I write that? So I'm taking the derivative with respect to t. I have sine of something, which is itself a function of t. So I would just apply the chain rule here. I'm first going to take the derivative with respect to x of sine of x. I could write sine of x of t, but I'll just revert back to the sine of x here for simplicity. And then I would then multiply that times the derivative of the inside, you could say, with respect to t, times the derivative of x with respect to t. This might be a little bit counterintuitive to how you've applied the chain rule before when we only dealt with x's and y's, but all that's happening, I'm taking the derivative of the outside of the sine of something with respect to the something, in this case it is x, and then I'm taking the derivative of the something, in this case x, with respect to t. Well, we can do the same thing here for this second term here. So I'd wanna take the derivative with respect to y of, I guess you could say the outside, of cosine of y, and then I would multiply that times the derivative of y with respect to t. And then all of that is going to be equal to what? Well, the derivative with respect to t of a constant, square root of two is a constant, it's not gonna change as t changes, so its derivative, its rate of change is zero. All right, so now we just have to figure out all of these things.