.
1. . P Q, . , (.7.1).
, :
/ = Q / P. (7.1)
RC = P + Q : RC = P + Q.
(7.1) : M C = = P × - Q × = 0.
, : RC ¹ 0, M C = 0. , , , :
, , , .
, , Q a. , .
2. . P Q, , , (.7.1).
, - (7.1) , .
RC = P + Q : RC = Q - P.
- : M C = = P × - Q × = 0,
, , , , .
3. . . , Q .
Q (7.1) / 1. , , .
RC 0, :
MC = P × - Q × = P ( - ) = P × B.
, , RC = 0, MC ¹ 0, , . ,
.