Yes, of course we can do that for normal periodic solutions. but for period-2 limit cycles this mothed would not work( period-2 limit cycle would have like two envelopes. That is the reason why I try to find the local extrema during the process.
Yes, of course we can do that for normal periodic solutions. but for period-2 limit cycles this mothed would not work( period-2 limit cycle would have like two envelopes. That is the reason why I try to find the local extrema during the process.