> Multivariable chain rule is much simpler than the 18 months learning curve would imply. .... We could probably teach it to a sufficiently logically apt high-s

> Multivariable chain rule is much simpler than the 18 months learning curve would imply. .... We could probably teach it to a sufficiently logically apt high-schooler within a week, provided we could find a sufficiently motivating use-case. Supposing this were the case, given that there's no shortage of homeschooling and "alternative" high schools out there, can you find a case where this has actually happened.