أرسل هذا في رسالة قصيرة: The compound equation related to the Bessel-Helmholtz equation and the Bessel-Klein-Gordon equation

 _    _     _____     _____     _____    ______   
| \  / ||  |  ___||  /  ___||  |  ___|| |      \\ 
|  \/  ||  | ||__   | // __    | ||__   |  --  // 
| .  . ||  | ||__   | \\_\ ||  | ||__   |  --  \\ 
|_|\/|_||  |_____||  \____//   |_____|| |______// 
`-`  `-`   `-----`    `---`    `-----`  `------`