And so we're essentially done. We just have to substitute what we found using the chain rule back into our original expression. The derivative of this business up here is going to be equal to, let me just copy and paste everything just to make everything nice and clean. So copy and paste. So that is going to be equal to this times cosine e to the x. So this is going to be, let's see, we could put the e to the x out front. We could put the negative out front.