Quote by mathwonk
what is del ? or nabla, or whatever?
what is A? presumably A is the vector of coordinates of the differential one form Ar dr + Atheta dtheta, but maybe not?
what coordinates are yoiu using? spherical? are del and A both in spherical coords?
this very old fashioned notation is just to me a clumsy way of obscuring the quite simple differential calculus as now used in terms of differential forms, and it is so out of date, i have never even seen it! (believe it or not.)
(i took elementary calculus out of loomis and sternberg and was never exposed to this old maxwellian version of vector calc notation, that originally arose using quatern ions, and has been outmoded in mathematics for over 50 years.)
but i agree it would be fun to see then turn out the same. but i am confident there is no difficuklty about this if we just make clear what the symbols mean.

yes, this is the expression in spherical coordinates.
This is the expression given for example in undergraduate electricity and magnetism formula when applying the curl of electric or magnetic fields (or of the vector potential) in spherical coordinates.