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Example of the desolve( ) function – Texas Instruments TITANIUM TI-89 User Manual

Page 444

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Differential Equation Graphing

444

By moving the trace cursor to trace each solution to

xc = 40

, you can find that:

The exact solution (

y1

) is 85.8486, rounded to six digits.

The

RK

solution (

Plot 1

) is 85.8952.

The

Euler

solution (

Plot 2

) is 85.6527.

You can also use the

Data/Matrix Editor

to open the errorlog data variable and scroll to

time = 40

.

Example of the deSolve( ) Function

Example of the deSolve( ) Function

Example of the deSolve( ) Function

Example of the deSolve( ) Function

The

deSolve( )

function lets you solve many 1st- and 2nd-order ordinary differential

equations exactly.

20. Press

… to trace, and then press C or D

until

y1

is selected. (1 shows in upper

right corner.) Then enter 40.

RK (Plot 1)

Euler (Plot 2)

Exact solution (y1)

y1 is selected when
1 shows here