#### Topic: Plugin to Plot Slope Fields

Attached is a plugin to plot slope fields, based on Benice's method of plotting the slope field as a parametric function.

Install the plugin file slopefield.py in the plugins folder before starting Graph.

Shortcut to plot slope field is: Ctrl+Shift+S

Input dy/dx based on x and y. The rectangle to plot the slope field in is defined by x-min (a) , x-max (b) , y-min (c), and y-max (d).

Input the number of equal subdivisions for the x-interval (m), and the number of equal subdivisions for the y-interval (n).

y' = f(x,y) (a<x<b, c<y<d).

* The interval [a,b] is divided into m equal subdivisions.

Let x0, x1, x2, ..., xm be the endpoints of the subdivisions.

* The interval [c,d] is divided into n equal subdivisions.

Let y0, y1, y2, ..., yn be the endpoints of the subdivisions.

* A small tangent segment is centered at each of the points

(xi, yj), for i = 0, 1, 2, ..., m and j = 0, 1, 2, ..., n,

showing the slope of the solution curve there.

* The slope field consists of the (m+1)(n+1) tangent segments.

Zoom square to make the segments look equal in length.