EULER (Numerical Version) - Casio 9800

Introduction
This program gives coordinates for an approximate solution for the differential equation ${\hbox{dy}\over \hbox{dx}}=\hbox{f(x,y\ )}$ using Euler's method.

If you have not used one of the programs posted on this website before, you should read through the information in the Intro to Programming section first.

The Program

'EULERNUM' {' is in ALPHA} {This is the name of the program}

"INITIAL X"?X {" is in ALPHA} {? is in PRGM} { is on the , button}

"INITIAL Y"?Y

"STEP SIZE"?H

0C {The 0 is a zero}

Lbl 1 {Lbl is in PRGM under JMP}

C+1C

X+HU

Y+Y1 H V {Y1 is in VAR under GPH, then followed by a 1}

"STEP NUMBER"

C { is in PRGM}

"X COORD"

U

"Y COORD"

V

UX

VY

Goto 1 {Goto is in PRGM under JMP}

Running the Program

You will need to enter a function f(x,y) into Y1 before running the program. The program will ask for an initial set of coordinates for X and Y and a stepsize. The stepsize can be either positive or negative. Hit EXE to see the X and Y coordinates of each iteration.

f(x,y) = x + y, Initial X = 1, Initial Y = 1, Stepsize = 0.1

Your answer will be
X = 1.1, Y = 1.2
X = 1.2, Y = 1.43
X = 1.3, Y = 1.693
X = 1.4, Y = 1.9923
and so on

'EULERNUM'	{' is in ALPHA} {This is the name of the program}
"INITIAL X"?X	{" is in ALPHA} {? is in PRGM} { is on the , button}
"INITIAL Y"?Y
"STEP SIZE"?H
0C	{The 0 is a zero}
Lbl 1	{Lbl is in PRGM under JMP}
C+1C
X+HU
Y+Y1 H V	{Y1 is in VAR under GPH, then followed by a 1}
"STEP NUMBER"
C	{ is in PRGM}
"X COORD"
U
"Y COORD"
V
UX
VY
Goto 1	{Goto is in PRGM under JMP}