Vector Fields, Divergence and Curl, and Flux and Circulation Integrals (robphy)

Topic:
Calculus
(The original 2019 version has been updated in 2022.) This is based on https://www.geogebra.org/m/XfmAAUTG (Vector Fields, Divergence, Curl, and Line Integrals  by  Erik Jacobsen) which is claimed to be based on (presumably) https://www.geogebra.org/m/UstetaTp (Vector Fields and Line Integrals by George Sturr). The "Purcell" vector fields are based on E.M. Purcell's Electricity and Magnetism textbook.