2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84328The Lorentz Transformations are derived without any linearity assumptions and without assuming that y and z coordinates transform in a Galilean manner. Status of the invariance of the speed of light is reduced from a foundation of the Special Theory of Relativity to just a property which allows to determine a value of the physical constant. While high level of rigour is maintained, this paper should be accessible to a second year university physics student.4 pages, no figuresGeneral Physicstext