to anyone interested in the algebraic use of differentials i would suggest reading keislers elementary infinitesimal calculus which is free online. basically you can define differentials in terms of infinitesimals where an infinitesimal € has the property €<r for all reals r. This use of infinitesimals has been shown to be rigourous through nonstandard analysis, although personally im happy with this intuitive definition.
what app is he using it seems helpful I want to get it
Nice video! I am a pretty mathematically rigorous person and it always annoys me when people (especially teachers) multiply by dx or dt without understanding what that step really means, I feel very reassured knowing that someone else is rigorous about this too and knows the difference
Where can I get some rigor?
take a shot every time he says "rigor"
does dy/dx = z mean that dx/dy = 1/z?
This makes sense