 
        Envelope Theorem - Example I
                                                                                                                            
                                                                                                                                                                                
                            Ma
                                                                                                                                                    
                                                                                                                                                                                
                            Wi
                                                            
            
                                 
                                     
         
         
                                     
         
         
         
         
         
         
         
         
                                     
         
                                     
         
         
         
         
         
         
                                     
         
         
         
         
        