Question Number 224884 by fkwow344 last updated on 09/Oct/25
$$\mathrm{solve}\:\mathrm{partial}\:\mathrm{differantial}\:\mathrm{equation} \\ $$$$\psi=−{k}^{\mathrm{2}} {g}^{\mu\nu} \bigtriangledown_{\alpha} \partial_{\beta} \psi\:,\:{k}\neq\mathrm{0} \\ $$$$\: \\ $$