. . . . :
- r, . , , t 1, t2...tn ( t1< t2....< tn), . - . - r(t) .
: = (t), = (t) z = = z(t) (..1.8), . Dt (.1.8), D r, , Dt. . 1.8 , . Dt .
. <v> Dt
Dt. Dt (1.1) ,
, , - .
, :
(1.3)
, X, Y Z.
, r :
, (1.4)
x,y z -. (1.4) (1.3),
(1.5) , . , : x(t), y(t) z (t) vx, vy, vz , .
( ) :
. (1.6)
- .