User manual - Chapter 3 Differential Equations

20010101
3-5 System of First Order Differential Equations
A system of first order differential equations, for example, has dependent variables (y1), (y2),
....., and (y9), and independent variable x. The example below shows a system of first order
differential equations.
(y1)쎾= (y2)
(y2)쎾= – (y1) + sin x
Set Up
1. From the Main Menu, enter the DIFF EQ Mode.
Execution
2. Press 4(SYS).
3. Enter the number of unknowns.
4. Enter the expression as shown below.
(y1) → Y1 (3(yn)b)
(y2) → Y2 (3(yn)c)
(y9) → Y9 (3(yn)j)
5. Specify the initial value for x0, (y1)0, (y2)0 and so on, if necessary.
6. Press 5(SET)b(Param).
7. Specify the calculation range.
8. Specify the step size for h.
9. Press 5(SET)c(Output).
Select the variable you want to graph, and then select a list for storage of the
calculation results.
10. Make V-Window settings.
11. Press 6(CALC) to solve the system of first order equations for y1, y2, and so on.
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3-5-1
System of First Order Differential Equations