Question 1102684
<pre>
There is no optimal value because it goes to infinity on the right
and to negative infinity on the left:

{{{graph(400,400,-200,200,-100,100,1.723+0.005x-0.0005x^2+0.00001528x^3)}}}

It crosses the x-axis at (-37.7474,0) and the y-axis at (0,1.732).
It has an inflection point at 


Edwin</pre>