suivant: Interactive plotting of solutions
monter: Graphs
précédent: Tangent field : plotfield
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Plotting a solution of a differential equation : plotode odeplot
Let f (t, y) be an expression depending of two variables
t and y.
- plotode(f (t, y),[t,y],[t0,y0]) draws the solution of
the differential equation y' = f (t, y) crossing through
the point (t0,y0) (i.e. such that
y(t0) = y0)
- By default, t goes in both directions. The range of value of t
may be specified by the optional argument
t=tmin..tmax.
- We can also represent, in the space or in the plane,
the solution of a differential equation
y' = f (t, y) where y = (X, Y) is a vector of size 2.
Just replace y by the variable names X, Y
and the initial value y0 by the two initial values of the
variables at time t0.
Input :
plotode(sin(t*y),[t,y],[0,1])
Output :
The graph of the solution of y'=sin(t,y) crossing through the point (0,1)
Input :
S:=odeplot([h-0.3*h*p, 0.3*h*p-p], [t,h,p],[0,0.3,0.7])
Output, the graph in the space of the solution of :
[h, p]' = [h - 0.3h*p, 0.3h*p - p] [h, p](0) = [0.3, 0.7]
To have a 2-d graph (in the plane), use the option
plane
S:=odeplot([h-0.3*h*p, 0.3*h*p-p], [t,h,p],[0,0.3,0.7],plane)
To compute the values of the solution, see
the section
.
suivant: Interactive plotting of solutions
monter: Graphs
précédent: Tangent field : plotfield
Table des matières
Index
giac documentation written by Renée De Graeve and Bernard Parisse