t 2.t'= 3.t'= V- Where u is the relative speed of two reference systems c is the speed of light,(x,t)and (x',t')are coordinates observed within the two different reference system 2 2 2 2 2 2 2 2 2 2 ' 1 ( ) 4. ' 1 ( ) 1 3. ' 1 ( ) 2. ' 1 ( ) 1 c u u c x t t c u u c t t c u u c x t t c u u c x t t             Where u is the relative speed of two reference systems c is the speed of light,(x,t) and (x’,t’) are coordinates observed within the two different reference system