⑩天掌 Teaching Plan on Advanced Mathematics 注意: 1.定积分的下限a一定要小于上限6 2.f(x,y)中x,y不彼此独立而是相互有关的 特殊情形 (1)L:y=y(x)a≤x≤b. f(x, y)ds=fIx,v(x)l1+y(x)dx. (a<b) tianjin Polytechnic univerityTianjin Polytechnic University Teaching Plan on Advanced Mathematics 注意: 1. 定积分的下限 一定要小于上限 ; 2. f (x, y)中x, y不彼此独立, 而是相互有关的. 特殊情形 (1) L : y =(x) a  x  b. ( , ) [ , ( )] 1 ( ) . 2 f x y ds f x x x dx b L a =  + (a  b)