Plotting a function not working correctly

[Alberto Candel]

Hi,

It looks like to be able to see the whole part of the graph that includes all roots, you need to set the x-range to include all roots, and the y-range to be at least the max/min of your polynomial over the selected x-range. In this case x from -15 to 15 and y from -100 to 100 seem to work. An estimate for the x-range can be easily found (Lagrange).