I really don't have any experience at figuring the trajectories -
My work with t/a is really based on psychology.
From my T/A 101 board:
...it is my contention that charting is a graphical representation of market sentiment using applied mathmatics to define and project both current and future tendencies, based on data that has been collected and analyzed.
I think it was Peter Lynch that said "Charts are 100% accurate at determining the past."
LOL - My take is "Yep, and people usually do the same thing over and over in similar situations, and if I can graph it and interpret it, I can profit from it.
4God