Solution
= Solution
On that leading orbit, averaging the divergence gives $\sigma=\mu[1-(3a+1)r^2/2]+O(\mu^2)=-\mu+O(\mu^2)<0$, so the cycle is stable.
= Solution
On that leading orbit, averaging the divergence gives $\sigma=\mu[1-(3a+1)r^2/2]+O(\mu^2)=-\mu+O(\mu^2)<0$, so the cycle is stable.