And you take the derivative of this, you get 1 25th times the first derivative of W, and then the derivative of this with respect to T is just 0. A constant obviously does not change with respect to T. And so we get this right over here. Now this is the second derivative in terms of the first derivative. But the question asks us, write the second derivative in terms of W. But lucky for us, we know how to express this as a function of W. They gave that to us in the problem. This was given. This is just me rewriting it in a different notation. So this is going to be the same thing as 1 over 25 times the derivative of W. And the derivative of W is this.