Hi Anke,

Thanks for reporting this!

Another user has already reported this on the video, so the development team has already taken note of this.

Since the focus of the video is an example of a derivative application, and not finding derivatives, it's not crucial to be able to understand how Sal differentiates the given function. I do agree, however, that it might be helpful for users to know about differentiation rules before watching this video and learning linearization.

Thanks for your feedback and contributions!