Originally Posted by

**Mathlv** This is one of my exercise problem regarding the limit lesson.

The problem: In the theory of relativity, the mass of a particle with velocity v is

$\displaystyle

m =\frac{m_{0}}{\sqrt{1-v^2/c^2}}

$

where $\displaystyle m_{0}$ is the mass of the particle at rest and c is the speed of light. What happen as $\displaystyle v \rightarrow c^-$ ?

I am thinking that the problem is asking me to find the limit of the equation above as v approaches c from the left, but I cannot get rid of the radical sign. I try to rationalize the denominator, but it does not lead me to an answer which I think is correct.

ANY HINT IS APPRECIATED.

Thanks