So this is going to be equal to derivative of cosine of something with respect to that something is equal to the negative sine of that something. Negative sine of e to the x. Once again, we can view this as the derivative of cosine of e to the x with respect to e to the x. And then we multiply that times the derivative of the something with respect to x. So let me do this in this. I'm running out of colors. Let me do this in this green color.