% It calculates ODE using Runge-Kutta 4th order method
% Author Ido Schwartz

clc; % Clears the screen
clear;
h=5; % step size
x = 0:h:100; % Calculates upto y(3)
Y = zeros(1,length(x));
y(1) = [-0.5;0.3;0.2];
% initial condition
F_xy = @(t,r) 3.*exp(-t)-0.4*r; % change the function as you desire

for i=1:(length(x)-1) % calculation loop
k_1 = F_xy(x(i),y(i));
k_2 = F_xy(x(i)+0.5*h,y(i)+0.5*h*k_1);
k_3 = F_xy((x(i)+0.5*h),(y(i)+0.5*h*k_2));
k_4 = F_xy((x(i)+h),(y(i)+k_3*h));

y(i+1) = y(i) + (1/6)*(k_1+2*k_2+2*k_3+k_4)*h; % main equation

end
display(Y(i+1));
if i run the programme i get answer =0;
how can i solve this problem if i have three initial condition -0.5 ,0.3 and 0.2
while x=0:5:100
and how i can plot the answer with respect to x?% It calculates ODE using Runge-Kutta 4th order method
% Author Ido Schwartz

clc; % Clears the screen
clear;
h=5; % step size
x = 0:h:100; % Calculates upto y(3)
Y = zeros(1,length(x));
y(1) = [-0.5;0.3;0.2];
% initial condition
F_xy = @(t,r) 3.*exp(-t)-0.4*r; % change the function as you desire

for i=1:(length(x)-1) % calculation loop
k_1 = F_xy(x(i),y(i));
k_2 = F_xy(x(i)+0.5*h,y(i)+0.5*h*k_1);
k_3 = F_xy((x(i)+0.5*h),(y(i)+0.5*h*k_2));
k_4 = F_xy((x(i)+h),(y(i)+k_3*h));

y(i+1) = y(i) + (1/6)*(k_1+2*k_2+2*k_3+k_4)*h; % main equation

end
display(Y(i+1));
if i run the programme i get answer =0;
how can i solve this problem if i have three initial condition -0.5 ,0.3 and 0.2
while x=0:5:100
and how i can plot the answer with respect to x? % It calculates ODE using Runge-Kutta 4th order method
% Author Ido Schwartz

clc; % Clears the screen
clear;
h=5; % step size
x = 0:h:100; % Calculates upto y(3)
Y = zeros(1,length(x));
y(1) = [-0.5;0.3;0.2];
% initial condition
F_xy = @(t,r) 3.*exp(-t)-0.4*r; % change the function as you desire

for i=1:(length(x)-1) % calculation loop
k_1 = F_xy(x(i),y(i));
k_2 = F_xy(x(i)+0.5*h,y(i)+0.5*h*k_1);
k_3 = F_xy((x(i)+0.5*h),(y(i)+0.5*h*k_2));
k_4 = F_xy((x(i)+h),(y(i)+k_3*h));

y(i+1) = y(i) + (1/6)*(k_1+2*k_2+2*k_3+k_4)*h; % main equation

end
display(Y(i+1));
if i run the programme i get answer =0;
how can i solve this problem if i have three initial condition -0.5 ,0.3 and 0.2
while x=0:5:100
and how i can plot the answer with respect to x? runge-kutta 4th order method MATLAB Answers — New Questions

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