原式=∫x√[1-(x-1)^2]dx令x=1+sint,则dx=costdt原式=∫(1+sint)cos^2tdt=∫cos^2tdt+∫sintcos^2tdt=(1/2)*∫(1+cos2t)dt-∫cos^2td(cost)=(1/2)*[t+(1/2)*sin2t]+(1/3)*cos^3t+C=(1/2)*arcsin(x-1)+(1/2)*(x-1)*√(2x-x^2)+(1/3)*(2x-x^2)^(3/2)+C其中C是任意常数