The equation also has a solution that can be found numerically with ease, even though no formula exists for its solution.

f = @(t,u) sin( (t+u).^2 );

[t,u] = ode45(f,[0,4],-1);

plot(t,u)

xlabel('t'), ylabel('u(t)'), title('Solution of u''=sin[(t+u)^2]') % ignore this line