x2根号4x2dx要过程详细点谢谢∫x2/根号(4-x2)dx(三角换元，令x=2sint)=∫4(sint)^2/根号(4(cost)^2)d(2sint)=∫4(sint)^2/(2cost)*(2cost)dt=∫4(sint)^2dt(倍角公式cos2t=1-2(sint)^2)=∫2(1-cos2t)dt=2t-sin2t+C(将t=arcsin(x/2)带回)=2arcsin(x/2)-2(x/2)*根号(1-x^2/4)+C=2arcsin(x/2)-x/2*根号(4-x^2)+CC为任