Читать книгу RF/Microwave Engineering and Applications in Energy Systems - Abdullah Eroglu - Страница 27

In a spherical coordinate system, the differential length is given by

(1.41)

Its magnitude is defined by

(1.42)

Figure 1.10 Illustration of differential length, area, and volume in a cylindrical coordinate system.

The differential areas in a spherical coordinate system for the surface areas shown in Figure 1.11 are defined as

(1.43)

The infinitesimal change for the volume is defined by

(1.44)

The illustration of the changes in length, area, and volume for a spherical coordinate system is given in Figure 1.11.