Help for using Dfield at Dordt College
The Dfield solver is linked to the MATH 204 course page. Just
click on the icon. It might take a few minutes to load. Most of
the operation of this program is intuitive.
To get full credit your solution must show a dot at each initial
condition, and no other dots that would confuse the matter. You
may set initial conditions and place the dots by setting initial
conditions from the keyboard or by clicking on the point in the
direction field that corresponds to the initial condition. The
keyboard method is more accurate however. You should enter
initial conditions via the keyboard when they are given
numerically. In the "Direction Field" Window, from the top menu
click on "Solution" and then "Keyboard input of initial value."
If you are using the mouse to select an initial condition, just
before you click, you can read the initial condition in the lower
left corner of the direction field window. Write these numbers
down just before you click if you need them for an answer.
The bigger you make the direction field plot on your computer
screen the more accurately you can click on an initial condition
with your mouse cursor.
On Sec 2.8, Ex 1-1 any reasonably close results will get
full credit assuming that the initial conditions are correctly
noted numerically (e.g. "x(0) = 0.009") You may put Ex 1 - 4 on
one plot and Ex. 5-8 on another plot. Label each solution curve
with the Exercise number.
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