根据定义 P(x=im 2→01 设分点x,对应参数1，点(5，)对应参数x,由于 △x,=x,-x-1=p(t)-p(t-1)=p'()△ P(x,y)=lim∑P[o(),(3,】o'(z), →0 =1 因为L为光滑弧，所以p'()连续 ∑P().wG】p(,) i=l =∫2P1o0.wop'o) 同理可证 J2(xyiy=Qloo.w】wo)dr BEIJING UNIVERSITY OF POSTS AND TELECOMMUNICATIONS PRESS 目录上页下页返回结束目录 上页 下页 返回 结束 设分点 对应参数 根据定义 i x , i t , i  由于  i = i − i−1 x x x ( ) ( ) = i − i−1  t  t i i =()t P[ (t), (t)] dt  =      → = = n i P i i 1 0 lim [ ( ), ( )]  i i ()t  → = = n i P i i 1 0 lim [ ( ), ( )]  i i ( )t (t)  → = =  n i i i i P x 1 0 lim ( , )  对应参数 因为L 为光滑弧 , 同理可证 Q[ (t), (t)] d t  =     (t)