由柯西-黎曼条件:对u(x,y)=1/2ln(x^2+y^2)求x的偏导x/(x^2+y^2),
对u(x,y)=1/2ln(x^2+y^2)求x的偏导y/(x^2+y^2),
f'(z)=x/(x^2+y^2)-yi/(x^2+y^2)=1/z
f(z)=lnz+C
f(1+i)=1/2*ln2,C=-π/4*i
f(z)=lnz-π/4*i
由柯西-黎曼条件:对u(x,y)=1/2ln(x^2+y^2)求x的偏导x/(x^2+y^2),
对u(x,y)=1/2ln(x^2+y^2)求x的偏导y/(x^2+y^2),
f'(z)=x/(x^2+y^2)-yi/(x^2+y^2)=1/z
f(z)=lnz+C
f(1+i)=1/2*ln2,C=-π/4*i
f(z)=lnz-π/4*i