
x1=!random 1.8,2.25
x2=!random 1.8,2.25
xc=$[($x1+$x2)/(2*$rg)]
x0=$[($x2-$x1)/(2*$xc)]

y1=$[max(($x1)^3-3*$x1,2.1)]
y2=$[max(($x2)^3-3*$x2,2.1)]
ya=!random 1.3,1.9
yb=!random $ya-2,2-$ya
Y1=$[(-$ya+$yb)*$rg/2]
Y2=$[($ya+$yb)*$rg/2]
yc=$[$ya*$rg/($y1+$y2)]
y0=$[$Y1+$y1*$yc]

a3=$[$yc*($xc)^3]
a1=$[3*$yc*$xc]

f=!rawmath $a3*(t+$x0)^3-$a1*(t+$x0)+$y0

