Creating Direction Fields with DERIVE 5
Last updated: January 22, 2007
Steve Billups,
modified by Lance Lana
This tutorial describes how to use DERIVE 5 to generate a direction field for the first
order differential equation:
dy
--
= r(x,y)
dx
Direction fields can be created using the function DIRECTION_FIELD.
The
DIRECTION_FIELD function has the following syntax:
DIRECTION_FIELD(r,x,x0,xm,m,y,y0,yn,n)
r
= right hand side function r(x,y)
x
= name of the independent variable
y
= name of the dependent variable
x0 = lower bound on the x values to be plotted.
xm = upper bound on the x values to be plotted.
m
= number of steps in the x direction
y0 = lower bound on the y values
yn = upper bound on the y values
n
= number of steps in the y direction
The following is an example of how you can use this function to generate a direction field
for the ODE
dy
--
= y-x
dx
Hint: use
x
, not
t.
1.
Define the function by typing the following in the

This ** preview** has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*