發送短信 : Existence of solutions for singular boundary problems for higher order differential equations

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