1550078481-Ordinary_Differential_Equations__Roberts_

PORTRAIT User's Guide 529

ii PORTRAIT l!liliJf!3

Enter the system defining functions Fl. F2

y'l = Fl = lY1·.5'y1•y2.

Enter the number of initial value problems lo solve

y'2 = F2 = l·2"y2+.25"y1"y2

For each initial value problem i. enter the interval of integration [ai. biJAhe initial value ct

and·ttte initial conditions dli an~ d2i.

a i = b i = c i =. dli = d2i =

4.5 5 5

VERIFY

ai,b i. c i. dli, tl2i

Figure B.3 System Definition Screen with Input Data

After checking to see t hat the values for the interval of integration and the
init ial conditions are entered correctly, we click the VERIFY button. This
causes t he INTEGRATE button to appear. Clicking the INTEGRATE button
allows the computer to numerically solve the specified initial value problem
and to display the option screen shown in Figure B.4 on the monitor.

Ii. PORTRAIT li!iliJ l!3

Enter the system defining functions Fl, F2 Enter the number of initial value problem• to solve

y'l = F1 = Jy1. 5'y1 "y2

y'2 = F2 = :=:::=============-=====J·2'y2+.25"y1"y2 ~

N = 2

For each initial value P.roblem i, enter the interval qi integration [ai, bi], the initial value ci,

and the initial conditions dli and d2i.

i = a i"' bi=

IT J __ _, 4.5

OPTIONS

For IVPs already solved

f': [f!~tf~solu!_f~~~:G!'!e.!i°~both component~

r PHASE-PLANE graph of any subset of IVPs

r PRINT solution on monitor

Other

c i = dli =

RERUN current IVP with aifferent interval of integration or initial conditions

r. INPUT CONDITIONS for next IVP to be solved

Figure B.4 Option Screen

d2i =