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

  _____      ___      ______    _____     _____   
 / ____||   / _ \\   /_   _//  |  ___||  / ____|| 
/ //---`'  | / \ ||  `-| |,-   | ||__   / //---`' 
\ \\___    | \_/ ||    | ||    | ||__   \ \\___   
 \_____||   \___//     |_||    |_____||  \_____|| 
  `----`    `---`      `-`'    `-----`    `----`