It looks like an alternating series, so It’s likely from a physics class involving electrostatic or maybe control systems. It also could be from a later calculus class where you’re first introduced to alternating series like Taylor or Leibniz.

Always start with a free-body diagram

Reading this gave me anxiety.

I think most engineers have an understanding amongst each other, regardless of their specialty, we can all teach ourselves to problem solve. So many math and physics classes as an EE just to get to my core classes. It definitely a certain type of person to get through the thick of it.

“nailed to your fire place” - aren’t these made of brick?