设f(z)=u+iv为解析函数,则由Cauchy-Riemann方程知∂v/∂x=-∂u/∂y=-x+2y;∂v/∂y=∂u/∂x=2x+y。v=-x^2/2+2xy+y^2/2+C,C为常数。f(z)=u+iv=x^2+xy-y^2+i(-x^2/2+2xy+y^2/2+C)=(1-i/2)(x^2+2ixy-y^2)+iC=(1-i/2)(x+iy)^2+iC=(1-i/2)z^2+iC,f(i)=-1+i代入,得C=1/2,f(z)=(1-i/2)z^2+i/2