function oscillatorONE
tic
clear

t = 160;
L=0.5;



x(1) = 0;
x(2) = 1;

options = odeset('RelTol',1e-7,'OutputFcn','odeplot','OutputSel',[1]);
[t x] = ode45(@o, [0:L:t], x, options);
toc

function dxdt = o(t,x)

a = 0;
k = 1;
k3 = 1;
m = 1;



dxdt(1) = x(2);
dxdt(2) = -(1/m)*(k*x(1) + k3*x(1)^3)- a*x(2);

dxdt = dxdt';