Оператор на Д'Аламбер: Разлика между версии

\Box & = \partial^\mu \partial_\mu = g^{\mu\nu} \partial_\nu \partial_\mu = \frac{1}{c^{2}} \frac{\partial^2}{\partial t^2} –- \frac{\partial^2}{\partial x^2} –- \frac{\partial^2}{\partial y^2} –- \frac{\partial^2}{\partial z^2} \\

& = \frac{1}{c^2} {\partial^2 \over \partial t^2} –- \nabla^2 = \frac{1}{c^2}{\partial^2 \over \partial t^2} –- \Delta ~~.