Subject: What is the relative mass of a particle at the velocity of light?

From the equation[sqrt(e^2/c^4-p^2/c^2)/sqrt(1-v^2/c^2)=relative mass] one 
can see that any particle traveling at the velocity of light must have 
rest mass of zero, and be traveling at the velocity of light(in a vacuum). 
This means that at the velocity of light relative mass is 0/0, which 
though undefined, has four logical answers:0,1,2,inf.  If one goes by x/x=1
then you have one, if you go by x/0=inf then you have infinity, if you go 
by 0/x=0 then you have zero, and if using L'Hospital's rule the answer is 
two.
This seems to me to correspond somewhat to the four forces(weak bosons 
having infinite mass at c)  I was asking because I wondered how the 
mathematically undefined answer was adressed by physicists and due to the 
fact that the four answers, one corresponding to the weak force, may have 
to do with bosons. It may also have to do with field theory as 0/0 is 
point slope but could have "length" as a string.  I would appreciate an 
answer untailored to my age.  Thanks!!

Re: What is the relative mass of a particle at the velocity of light?