Texas Instruments TI-89 Manual Book page 211

Note: errorlog lets you
combine the data in rklog
and eulerlog so that you can
view the two sets of data
side by side.
Note: rklog[1] and rklog[2]
refer to column 1 and 2 in
rklog , respectively. Likewise
with eulerlog[2] .
Tip: Scroll through the data
variable to see how the RK
and Euler values differ for
the same time value.
Note: To see how to use
deSolve() to find this exact,
general solution, refer to
page 196.
194 Chapter 11: Differential Equation Graphing
9. Return to the Home screen,
and use to create a
BldData
data variable containing the
graphing points.
Euler
10. Use the Data/Matrix Editor
( O
) to create a new
6 3
data variable named
11. In this new data variable,
define the , , and
c1 c2
column headers to refer to
data in rklog and eulerlog
Also, enter column titles as
shown.
To define a column header,
move the cursor to that
column, press †, type the
reference expression (such
as for ), and press
rklog[1] c1
¸.
12. In the Data/Matrix Editor,
press „. Then press ƒ and
define Plot 1 for the RK data,
as shown to the right.
13. Define Plot 2 for the Euler
data. Use the values shown
to the right.
14. Return to the Y= Editor,
press 3, and set
Graph = FUNCTION
15. The exact solution to the
differential equation is given
below. Enter it as
y1
y1 = (100ù e ^(x/10))/(
BldData eulerlog
.
errorlog
c3
.
Plot Type=xyline
Mark=Cross
x=c1
y=c3
.
.
e ^(x/10)+9)
You can use C to scroll up to see
Plot 1 and Plot 2.
c1=rklog[1] or
c1=eulerlog[1]
c2=rklog[2]
c3=
eulerlog[2]