.
, , .
, , , - , (. 3.2).
, (*, *):
* >0,*> 0, ^* + * = /. (3.3)
, , .
, (3.3), :
̲^ < - /. (3.4)
8 " / , , - , , ( ', ). :
= ̲^. (3.5)
"" , . , - ?
(, ). "": ( + , + ), :
/ + ˲ = ( +)+ ( + ) =+ + + .
. , :
˲ = + .
, (3.5). :
˲ = + = + 8 = ( + ^^ (3.4), : +$<-(/) = 0.
:
˲/ =+ 8 < 0.
> 0, (3.4) < 0. , . , , , "" .
, (3.4) , - , : "" (. . 3.15, N "" ).
( !) "" ( ).
, - , . - (3.4) .
ֳ
̲ >-/. 쳿 , .
, . (, ) . , , "" , .
:
.
MRSAB=-PA/PB.
.
(2.5): MUA / = MUB / , :
MUA/ MU = / = -MRSAB, (3.6)