I want to tell something about electrical engineering.....
The Electro Magnetic theory....... For learning EMT you need to get the basic ideas about
CCS(Cylindrical Coordinate System)
SCS(Spherical Coordinate System)
RCS(Rectangular Coordinate System
The best book for reference is Electromagnetics 2/ed by Joseph A Edminister.
This book is available in 2d shared and the link is given below........