發送短信 : Stability analysis of epidemic model with varrying total population size and constant immigration rate

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