Texas Instruments TI-92 Owners Manual - Page 192

Differential Equation Graphing - troubleshooting

Page 192 highlights

Chapter 11: Differential Equation Graphing 11 Preview of Differential Equation Graphing 176 Overview of Steps in Graphing Differential Equations 178 Differences in Diff Equations and Function Graphing 179 Setting the Initial Conditions 184 Defining a System for Higher-Order Equations 186 Example of a 2nd-Order Equation 187 Example of a 3rd-Order Equation 189 Setting Axes for Time or Custom Plots 190 Example of Time and Custom Axes 191 Example Comparison of RK and Euler 193 Example of the deSolve( ) Function 196 Troubleshooting with the Fields Graph Format 197 Note: A differential equation is: • 1st-order when only 1st-order derivatives appear. • Ordinary when all the derivatives are with respect to the same independent variable. This chapter describes how to solve differential equations graphically on the TI-89 / TI-92 Plus. Before using this chapter, you should be familiar with Chapter 6: Basic Function Graphing. The TI-89 / TI-92 Plus solves 1st-order systems of ordinary differential equations. For example: y' = .001 y ù (100 ì y) or coupled 1st-order differential equations such as: y1' = ë y1 + 0.1 ù y1 ù y2 y2' = 3 ù y2 ì y1 ù y2 You can solve higher-order equations by defining them as a system of 1st-order equations. For example: y'' + y = sin(t) can be defined as y1' = y2 y2' = ë y1 + sin(t) By setting appropriate initial conditions, you can graph a particular solution curve of a differential equation. You can also graph a slope or direction field that helps you visualize the behavior of the entire family of solution curves. For graphing, the TI-89 / TI-92 Plus uses numerical methods that approximate the true solutions. The deSolve() function lets you solve some differential equations symbolically. This chapter introduces deSolve(). Refer to Appendix A for more details. Chapter 11: Differential Equation Graphing 175

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Chapter 11: Differential Equation Graphing
175
Differential Equation Graphing
Preview of Differential Equation Graphing
........................................
176
Overview of Steps in Graphing Differential Equations
.....................
178
Differences in Diff Equations and Function Graphing
......................
179
Setting the Initial Conditions
................................................................
184
Defining a System for Higher-Order Equations
.................................
186
Example of a 2nd-Order Equation
.......................................................
187
Example of a 3rd-Order Equation
........................................................
189
Setting Axes for Time or Custom Plots
...............................................
190
Example of Time and Custom Axes
....................................................
191
Example Comparison of RK and Euler
...............................................
193
Example of the deSolve( ) Function
....................................................
196
Troubleshooting with the Fields Graph Format
................................
197
This chapter describes how to solve differential equations
graphically on the
TI
-
89 / TI
-
92 Plus
. Before using this chapter, you
should be familiar with Chapter 6: Basic Function Graphing.
The
TI
-
89 / TI
-
92 Plus
solves 1st-order systems of ordinary
differential equations. For example:
y' = .001 y
ù
(100
ì
y)
or coupled 1st-order differential equations such as:
y1' =
ë
y1 + 0.1
ù
y1
ù
y2
y2' = 3
ù
y2
ì
y1
ù
y2
You can solve higher-order equations by defining them as a
system of 1st-order equations. For example:
y'' + y = sin(t)
can be defined as
y1' = y2
y2' =
ë
y1 + sin(t)
By setting appropriate initial conditions, you can graph a
particular solution curve of a differential equation.
You can also graph a slope
or direction field that helps
you visualize the behavior of
the entire family of solution
curves.
For graphing, the
TI
-
89 / TI
-
92 Plus
uses numerical methods that
approximate the true solutions. The
deSolve()
function lets you
solve some differential equations symbolically. This chapter
introduces
deSolve()
. Refer to Appendix A for more details.
11
Note:
A differential equation
is:
1st-order
when only
1st-order derivatives
appear.
Ordinary
when all the
derivatives are with
respect to the same
independent variable.