global a
figure
hold on	
for a=1:0.2:3
t0=0.;
tf=6.;
x0=[1,0]';
options = odeset('AbsTol',[1e-7 1e-7]);
[t,x]=ode45('tut2_eq',[t0 tf],x0,options);
plot(t,x(:,1))
end
