This applet let you play with polynomial y=f(x)=a*x[sup]3[/sup]+b*x[sup]2[/sup]+c*x+d
You can drag two points x1,x2 along the function.
It will calculate the integral between x1 and x2, the slope at those two points will be shown if you enable the checkbox.
The slider at the right let you change the scale in the Y-axis.
$y=f(x)=ax^3+bx^2+cx+d$