User:Mhariharan55

I have a very short alternative proof.

When F=ma, =m c/t                               @ c light velocity c=s/t                                    [s=displacement] s=ct Work done= F s                              [s=displacement] =(m c/t) (ct) W=mc2 By Work-Energy Principle,work is nothing but energy, W=E Thus,   E=mc2 Hence proved.