lambda = 2000;
f = @(t,y) -lambda*y + t;
y0 = 0;
tspan = [0 1];
opts = odeset('RelTol',1e-12,'AbsTol',1e-14);
[t2,y2] = ode15s(f,tspan,y0,opts);
plot(t2,y2)
print -dpng "plot.png"