MNE - EDO Método de Euler Simples

clc;
clear all;
close all;

fxy='-1.2*y+7*exp(-0.3*x)';
dfxy='-1.2';
h=0.5;
%h=0.1;
%h=0.01;
a=0;
b=2.5;
n=(b-a)/h;
Y0=3;
X0=a;
Y(1)=Y0;
X(1)=X0;

% Euler Simples
for i=1:n
    disp('----------------------------------------------------------------')
    disp(['Iteração' num2str(i)])
    y=Y(i);
    disp([[['y' num2str(i)] '='] num2str(y)])
    x=X(i);
    disp([[['x' num2str(i)] '='] num2str(x)])
    disp(['f(x,y) -> ' fxy])
    Fxy(i)=eval(fxy);
    disp([[[[['f(x' num2str(i)] ',y'] num2str(i)] ')='] num2str(Fxy(i))])
    X(i+1)=x+h;
    Y(i+1)=y+h*Fxy(i);
    disp([[[['x' num2str(i+1)] ' = '] ['x' num2str(i)]] ' + h'])
    disp([[['x' num2str(i+1)] '='] num2str(X(i+1))])
    disp([[[['y' num2str(i+1)] ' = '] ['y' num2str(i)]] [[' + ' [[[['f(x' num2str(i)] ',y'] num2str(i)] ')'] ] '*h']])
    disp([[['y' num2str(i+1)] '='] num2str(Y(i+1))])
end

XX=a:0.01:b;
YY=(70/9)*exp(-0.3*XX)-(43/9)*exp(-1.2*XX);
plot(X,Y,'r*',XX,YY)