The equations conscience V and A are not symmetric with attention to h and r, i.e. the influence of h and r on 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://en-web-directory.com/listings12747941/nouvelle-%C3%A9tape-par-%C3%A9tape-carte-pour-%C3%89dition-pdf