释义 |
Helmholtz Differential Equation--Cartesian CoordinatesIn 2-D Cartesian Coordinates, attempt Separation of Variables by writing
 | (1) |
then the Helmholtz Differential Equation becomes
 | (2) |
Dividing both sides by gives
 | (3) |
This leads to the two coupled ordinary differential equations with a separation constant ,
where and could be interchanged depending on the boundary conditions. These have solutions
The general solution is then
 | (8) |
In 3-D Cartesian Coordinates, attempt Separation of Variables by writing
 | (9) |
then the Helmholtz Differential Equation becomes
 | (10) |
Dividing both sides by gives
 | (11) |
This leads to the three coupled differential equations
where , , and could be permuted depending on boundary conditions. The general solution is therefore | |  | (15) |
References
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 501-502, 513-514 and 656, 1953. |