Actually I could observe how to answer the question U(R) = (L/R) / ((L/R) + 2 Tprob) Now: by taking the limit:
lim 'R→ ∞' U(R) = lim 'R→ ∞' (L/R) / ((L/R) + 2 Tprob)
put R = ∞, we get:
(L/∞) / ((L/∞) + 2 Tprob) = 0 / (0+2Tprop) = 0
the same for lim 'R→ 0+'.
Also, the same for the throughput.
After we get the limits, we can plot the graph easily according to the values we get.
Regards,