It is equivalent to` C=C_(1)+(C_(2)C_(3))/(C_(2)+C_(3))`
`C=(A_(1)K_(2)in_(0))/(d_(1)+d_(2))+((A_(2)K_(2)in_(0))/(d_(1)).(A_(2)K_(3)in_(0))/(d_(1)))/((A_(2)K_(2)in_(0))/(d_(1))+(A_(2)K_(3)in_(0))/(d_(2)))`
`=(A_(1)K_(1)in_(0))/(d_(1)+d_(2))+(A_(2)^(2)K_(2)K_(3)in_(0))/(A_(2)K_(2)in_(0)d_(2)+A_(2)K_(2)in_(0)d_(1))`
`=(A_(1)K_(2)in_(0))/(d_(1)+d_(2))+(A_(2)^(2)K_(2)K_(3)in_(0))/(K_(2)d_(2)+K_(3)d_(1))`