# Using the improved Euler (Huen) method, determine the approximate solution y (t) of the following starting problem:

3 views (last 30 days)
Klaudia Szczepanska on 28 May 2021
Commented: Rena Berman on 29 Jun 2021
Using the improved Euler (Huen) method, determine the approximate solution y (t) of the following starting problem:
dy / dt = y * e ^ 5t, y (0) = 1; t; [0, 0.5]
for time steps: h = ½; h = ¼; h = 1/8; h = 1/16; h = 1/32;
Then solve the above differential equation using the separated variables method. Compare the obtained numerical results on the graph with the exact solution y (t). Calculate the global error en for each of the time steps h and determine on this basis the order of the improved Euler (Huen) method. I have to solve it in Matlab, but I have problem with doing the script. If anyone would provide me to simple code for the solution, it would be really helpfull for me. Thank you for all the answers and tips :)
Rena Berman on 29 Jun 2021

Torsten on 28 May 2021
Edited: Jan on 28 May 2021
Untested !
function main
H = [1/2 ,1/4,1/8,1/16,1/32];
t0 = 0;
t1 = 0.5;
y0 = 1;
f = @(t,y) y*exp(5*t);
for i= 1:numel(H)
h = H(i);
t = (t0:h:t1).' ;
N = numel(t);
y = zeros(N,1);
y(1) = y0;
for j = 2:N
yhelp = y(j-1) + h*f(t(j-1),y(j-1));
y(j) = 0.5*y(j-1) + 0.5*(yhelp + h*f(t(j),yhelp));
end
T{i} = t;
Y{i} = y;
end
plot(T,Y)
end
Torsten on 29 May 2021
@Jan: Thank you for formatting.