A note on the conversion of the tangent formula to an optimization problem

It is shown that the sets of phase angles of a structure which satisfy the tangent formula correspond also to extremal values of a function G = - ⅙ | E_hE_kE_{h - k}| cos (φ_k + φ_{h - k}- φ_h). This fact may simplify the computational implementation of the tangent formula and those of its extensions that can also be formulated as optimization problems.