(3) √x+√y=1, 则 x≥0, y≥0, 与坐标轴交于 (0,1),(1,0),则
S =∫ ydx =∫ (1-√x)^2dx =∫ (1-2√x+x)dx
= [x-4x^(3/2)/3+x^2/2] = 1-4/3+1/2 = 1/6.
(3) √x+√y=1, 则 x≥0, y≥0, 与坐标轴交于 (0,1),(1,0),则
S =∫ ydx =∫ (1-√x)^2dx =∫ (1-2√x+x)dx
= [x-4x^(3/2)/3+x^2/2] = 1-4/3+1/2 = 1/6.