For convenience we can choose the constant to be κ − 1 R 2 {\displaystyle \kappa ^{-1}R^{2}} where R 2 {\displaystyle R^{2}\,} now is positive and κ ≡ ± 1 {\displaystyle \kappa \equiv \pm 1} .
За погодност можеме да избереме константата да биде κ − 1 R 2 {\displaystyle \kappa ^{-1}R^{2}} каде R 2 {\displaystyle R^{2}\,} е позитивна и κ ≡ ± 1 {\displaystyle \kappa \equiv \pm 1} .