x=p(1) 上(3)推广r:1{y=v(,:点a,终点月 z=(t) 「Pd+g+Rk =P19(,y(),o()p( +Q|(t),y(t),o(t)y'(t) + rio(t), y(t), a(tJo(tdt 上页, , . ( ) ( ) ( ) (3) :      推广 t起点 终点 z t y t x t      = = =  R t t t t dt Q t t t t P t t t t Pdx Qdy Rdz [ ( ), ( ), ( )] ( )} [ ( ), ( ), ( )] ( ) { [ ( ), ( ), ( )] ( )               +  +  =  + +  