
function [deriv]=systeme(t,y), 
    deriv(1)=y(2),
    deriv(2)=-y(1),
endfunction
                

t=[0:0.1:100*%pi];
tolA=1d-4;
tolR=1d-10;
y=ode("rkf",[1;0],0,t,tolR,tolA,systeme);
                
figC=scf();
plot2d(t,y(1,:)-cos(t))
