题目设L是以(0,0)为圆心,1为半径的单位圆周,则弧长积分int_(L) |y| , ds=A. 1B. 2C. 3D. 4设$L$是以$(0,0)$为圆心,1为半径的单位圆周,则弧长积分$\int_{L} |y| \, ds=$A. 1B. 2C. 3D. 4题目解答答案D. 4