仮定紙

f(z)=(az+b)/(cz+d)
a=0
b=1
c=1
d=0
f(z)=(az+b)/(cz+d)
f(z)=(0z+1)/(1z+0)
f(z)=(0+1)/(1z+0)
f(z)=(1)/(1z)
f(z)=1/1z
f(z)=1/z