Z=x+bZ'=1y=1/(x+b)=Z^(-1)y'=(-1)*Z^(-1-1)*Z'=-Z^(-2)*1=-1/(x+b)^2不设Zy'=-1/(x+b)^2*1=-1/(x+b)^2
Y=1/x+b,求导Y'=1'*(x+b)-1*(x+b)'/(x+b)2,Y'=-x/x2+2xb+b2.
