Just a couple of physics notes: I wrote r as a scalar. This is the magnitude of the vector r.; The 1 over 4πε 0 is just a constant.; Electric potential is a scalar quantity, not a vector.

The plot function creates a 2D plot with the slope-intercept form of the equation, and the (x,-10,10) part specifies the range of the graph, between the x values of -10 and 10. This will also be ...