The equations for V and A are not symmetric with considération to h and r, i.e. the influence of h and r je the problem are inherently different. We need to write A in terms of purely 1 variable. We use the constraint equation and choose to write h in https://directoryweburl.com/listings12745669/le-meilleur-c%C3%B4t%C3%A9-de-conversion-pdf