I defined a function that should give me an array with 3 elements, but when I use it it's giving me a lot more than 3.

function [t,x,N] = lab1(V0,mu,tf) %V0=10  mu=0.4  tf=1

W=1;
g=32.2;
r=5;

tspan=linspace(0,tf,1000);
x0=[0;V0/r];
param=g/r;
[t,x]=ode45(@EOM,tspan,x0,[],param,mu);

% replace 0 below by the expression of N
N=W*r*x(2) + W*g*cos(x(1));


function g=EOM(t,x,param,mu)

% replace 0 below by the expression of G2
g(1,1)=x(2);
g(2,1)=-mu*x(2)^2 + param*(mu*cos(x(1)) - sin(x(1)));

Answer 1

[Torsten]

Maybe you mean

V0=10;
mu=0.4 ; 
tf=1;
[t,x,N] = lab1(V0,mu,tf);
hold on 
plot(t,x)
plot(t,N)
hold off
grid on

function [t,x,N] = lab1(V0,mu,tf) %V0=10  mu=0.4  tf=1
  W=1;
  g=32.2;
  r=5;

  tspan=linspace(0,tf,1000);
  x0=[0;V0/r];
  param=g/r;
  [t,x]=ode45(@(t,x)EOM(t,x,param,mu),tspan,x0);

  % replace 0 below by the expression of N
  N=W*r*x(:,2) + W*g*cos(x(:,1));
  
end

function g=EOM(t,x,param,mu)
  % replace 0 below by the expression of G2
  g(1,1)=x(2);
  g(2,1)=-mu*x(2)^2 + param*(mu*cos(x(1)) - sin(x(1)));
end

If not, you will have to tell us which 3 elements you want to get.

[Melhem]

Thanks a lot. I've learned MATLAB a very long time ago and I'm a little bit rusty.