Related to
BTW, your problem is convex:
\frac{{3x + 1}}{{2x + 2}} = \frac{3}{2} - \frac{1}{{x + 1}} \ge y
you never get the optimal value \frac{{3}}{{ 2}} unless x=+ \infty
Related to
BTW, your problem is convex:
\frac{{3x + 1}}{{2x + 2}} = \frac{3}{2} - \frac{1}{{x + 1}} \ge y
you never get the optimal value \frac{{3}}{{ 2}} unless x=+ \infty