                                         563



 ,      Copper   
 $1,80  ,        5%  . -
 ,        Copper 
11%       $40. , , 
 = 2,70,  ,     ^ ($1,80/$2,70).  , 
  -    Copper,  
  (18.43),  11,7 (0,6667  (1 + 0,05)/(011 - 0,05)).   -
,    -    Copper, -
 14,8 ($40/$2,70),     .

18.6.3     

 ,    DDM -    ,  -
 ,         
    ,       
.          -
        (V^-)  -
       (V^):

^=^.+^,=^__++'                  (18.27)
,-i(l+k)'   (k-g)(l+k)

  ,           
  ?g     ,    0   .

, = , (1 + ^,) (1 + ^) ... (1 + g,).                   (18.44)

          t  
   ,     ,   (18.44) , :

D, = ,, = ,, (1 + ^,) (1 + ^) ... (1 + g,).                (18.45)

    (18.37)    (18.45)    
         -
     :

 ^,(1+^,) ^(l+gJO+g.a) ^ ^
E    (1+^)'         (1+^)2

^^0+^)(1+^)-0+^)^

(l+k^
^(1+g)(l+^)...(l+g^)(l+g)

(k-g) (l+k)7



   Magnesium.     $55,    
       $3  $0,75 .  
      ,       
 :

Z, = $2,00;       , = $5,00;       ^, = 67%;       , = 40%;

D, = $3,00;       ?, = $6,00;       ^ = 20%;      ^ = 50%.