3.把下列函数在指定的圆环域内展开为洛朗级数:-|||-(1) dfrac (1+2z)(({z)^2+1)(z-2)} https:/img.cdnjtzy.com/zyb_41d83bbff624efd82a285864b6d41680.jpglt |z|lt 2;-|||-(2) dfrac (1)({z)^2(z-1)} 在圆环域 https:/img.cdnjtzy.com/zyb_41d83bbff624efd82a285864b6d41680.jpglt |z-1|lt +infty 内展开;-|||-(3) (e)^dfrac (1{z-1)} ,lt |z-1|lt +infty ,