答：∫xf(x)dx=x/√(1-x²)+C两边求导得：xf(x)=1/√(1-x²)+(-x/2)*(-2x)/[(1-x²)√(1-x²)]=(1-x²+x²)/[(1-x²)√(1-x²)]=1/[(1-x²)√(1-x²)]1/f(x)=x(1-x²)^...