So it's going to be negative two cosine of x. Negative two cosine of x for x is less than zero. And then for x is greater than zero, I'll do this in another color, I'll do it in orange. We have this case right over here. And we'll just do the chain rule, derivative of negative four x with respect to x is negative four. And derivative of e to the negative four x with respect to e, the derivative of e to the negative four x with respect to negative four x is just e to the negative four x. Sometimes you can say this is derivative of the inside times the derivative of the outside with respect to the inside.