I have created a fifth and sixth power regression model through excel to fit two sets of data respectively. Now, I want to calculate the derivatives for both sets of data using my polynomial model. When I go to graph the fifth degree polynomial, all I get on Desmos, Geogebra, and my TI-83 Plus is a vertical line as though the relationship of the data is undefined. On Excel, a rather nice curve comes as the equation of the line.

How do I resolve this and what does this mean? A response will be hugely appreciated and needed.