The plotfield
or fieldplot
command draws the tangent field of a differential equation or a vector field.
To draw the tangent field of a differential equation,
plotfield takes two mandatory arguments and one
optional argument:
expr, an expression depending on two variables, a
time variable and a dependent variable.
vars, a list of the two variables [t,y], where
t is the time variable and y is the dependent variable. The
variables can optionally include their ranges; [t=a..b,y=c..d].
Optionally, ystep=n to specify the discretization.
plotfield(expr,vars ⟨,ystep=n ⟩)
draws the tangent field of the differential equation y′=f(t,y).
To draw a vector field plotfield takes two mandatory arguments and two
optional arguments:
V, a list of two expressions involving two variables.
vars, a list of the two variables. The
variables can optionally include their ranges var=a..b.
Optionally, xstep=n to specify the discretization
of the first variable.
Optionally, ystep=m to specify the discretization
of the second variable.
plotfield(V,vars ⟨,xstep=n,ystep=m ⟩)
draws the vector field given by V.
