I was watching the first episode of Det.Yakumo, and I happened to catch this screen:
We just recently learnt about sinh(x) and cosh(x), we didn’t exactly cover their derivatives yet, but the derivative on the board matches wikipedia. I guess the derivative makes sense, at first I had thought that since it was e^x, the derivative would be the same, but the e^-x probably changes the sign, making the cosh(x) derivative the same as the sinh(x) one. So, I guess the scary part was that I just learnt/am learning this stuff in calculus right now. Anyways, it was an interesting observation, so I felt like making it. I have seen other scenes in anime’s that also had “real” math on the board. I don’t remember which anime, but I think I saw one in which they were doing quadratics in like grade 8 or 9, that somewhat made me realize how difficult school in japan is (we didn’t learn that until grade 10).