Draws the graph of
fZ for the variable
Z = X⋅Y. Of course, it is
a⋅c < Z
<b⋅d.
Giving only integer values
for the parameters avoids issues of continuity in the graph.
The standard problem (above) yields case 1
(see the resolution by Glen et al. [2004]).
To obtain the other cases, it is suggested: d = 15,
and 18. With d = 6, an almost intuitive result
is obtained.
This is so confusing a problem if solved
analytically that Monte Carlo simulation would be
a safer alternative. | 
