Respuesta :
Starting with the equation:
[tex]E=mc^2[/tex]Divide both sides by m, provided that m is not equal to 0:
[tex]\begin{gathered} \frac{E}{m}=\frac{mc^2}{m} \\ \Rightarrow \\ \frac{E}{m}=c^2 \end{gathered}[/tex]Take the square root of both sides of the equation:
[tex]\sqrt[]{\frac{E}{m}}=\sqrt[]{c^2}[/tex]Remember that the square root of a squared number is equal to the absolute value of that number:
[tex]\sqrt[]{\frac{E}{m}}=|c|[/tex]This equation for c has two possibilities, whether c is positive or negative:
[tex]c=\pm\sqrt[]{\frac{E}{m}}[/tex]In the context of physics, only the positive value has a physical meaning.
