problem to create three graph in one Matlab file (explicit Euler, implicit Euler, Heun)

function taska

h = 0.1;

x = 0:h:pi;

y1 = [0];

%euler exlicit method

for i = 1:length(x)-1

y1(i+1)=y1(i)+h*f1(x(i),y1(i));

end

%heun's method

for i = 1:length(x)-1

x(i+1)=x(i)+h;

ynew=y1(i)+h*(f1(x(i),y1(i)));

y2(i+1)=y1(i)+(h/2)*(f1(x(i+1),y1(i))+h*(f1(x(i+1),ynew)));

end

%euler implicit method

for i = 1:length(x)-1

x(i+1)=x(i)+h;

ynew=y1(i)+h*(f1(x(i),y1(i)));

y3(i+1)=y1(i)+h*f1(x(i+1),ynew);

end

plot(x,y1,'g',x,y2,'r',x,y3,':')

end

function dy = f1(x,y1)

y0 = -1;

dx=0.01;

d = 50;

c1=(y0-(d^2/(d^2+1)));

dy=c1*exp(-dx)+d*(sin(x)/(d^2+1))+d^2*(cos(x)/d^2+1);

end

Answer 1

[Ameer Hamza]

Your code plot 3 graphs. But they are so close that it is difficult to see them separately. You can try the following line to plot the graphs()

plot(x,y1,'g-.+',x,y2,'b',x,y3,'m-')