function dydt = free25(t,y);
g = 9.81;
l = 1;
dydt = [y(2);-g/l.*sin(y(1))];
end
[t,y]= ode45('free25',[0 10],[0 0.09]);%I typed this in command window
plot(t,y(:,1));
refline([0 0]);
Error using feval Undefined function 'free25' for input arguments of type 'double'.
Error in odearguments (line 87) f0 = feval(ode,t0,y0,args{:}); % ODE15I sets args{1} to yp0.
Error in ode45 (line 115) odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Best Answer