I'm trying to solve a system of differential equations using Euler's method, but I don't know what the problem is with my code. If you can correct me the problem

clear

clc

clf

a= 0;

b= 2;

delta_x =0.5;

y1 (1) = 4;

y2 (1) = 6;

n= (b-a)/delta_x + 1 ;

x (1) = 0;

funcl =@(yl) - 0.5*yl ;

func2=@(y1, y2) 4 - 0.3* y2 - 0.1* yl ;

for i= 1:n-1

x(i+1)= i* delta_x;

y1 (i+1)= y1 (i) + delta_x * feval (funcl, yl (i));

y2 (i+1)= y2 (i)+ delta_x * feval (func2, y1 (i), y2 (i));

end

x

y1

y2

plot (x, y1, x, y2)

title('Plot of x va yi & y2 - Explicit Euler')

grid on

Answer 1

[Alan Stevens]

Don't confuse the number 1 with lower case l

a= 0;
b= 2; 
delta_x =0.5;
y1(1) = 4;
y2(1) = 6;
n= (b-a)/delta_x + 1 ;
x(1) = 0;
func1 =@(yl) - 0.5*yl ;
func2=@(y1, y2) 4 - 0.3* y2 - 0.1* y1 ;
for i= 1:n-1
x(i+1)= i* delta_x;
y1(i+1)= y1(i) + delta_x * feval(func1,y1(i));
y2(i+1)= y2(i)+ delta_x * feval(func2, y1(i),y2(i));
end
plot (x, y1, x, y2)
title('Plot of x va yi & y2 - Explicit Euler')
grid on 

[Ahmed Ali]

thank you so much . Oh, how can I make a mistake like this

Another thing, please. How can I display the values of x, y1 and y2

[Alan Stevens]

Just add the line

disp([x', y1', y2'])

[Ahmed Ali]

Thank you very much.bro @Alan Stevens