设C2上任一点坐标是B(x,y),则B关于A对称的点坐标是C(4-x,2-y),C在C1上,则有:
2-y=4-x+1/(4-x)
y=x-2-1/(4-x)
即g(x)=x-2+1/(x-4)
定义域x-4不=0,即(-无穷,4)U(4,+无穷)