I just think of the definition of a derivative.
d
is just an infinitesimally small delta. So dy/dx
is literally just lim (∆ -> 0) ∆y/∆x
.
which is the same as lim (x_1 -> x_0) [f(x_0) - f(x_1)] / [x_0 - x_1]
.
Note: ∆ -> 0
isn’t standard notation. But writing ∆x -> 0
requires another step of thinking: y = f(x)
therefore ∆y = ∆f(x) = f(x + ∆x) - f(x)
so you only need ∆x
approaching zero. But I prefer thinking d = lim (∆ -> 0) ∆
.
bhamlin@lemmy.world 6 days ago
If not fraction, why fraction shaped?
Amir@lemmy.ml 6 days ago
If you use exterior calculus notation, with d = exterior derivative, everything makes so much more sense