should quadratic drag be delved into if at all?
Depends on how prepared you are to openly and deliberately defame nesa, textbook authors, and multi-billion-dollar multinational publishers.
I'll give it a go.
As far as projectile motion with quadratic drag is concerned the current syllabus is complete garbage.
The mif and nsm textbook authors are complete amateurs, have no idea what they are talking about - and continued publication of their rubbish is doing a disservice to education in the schools that use their textbooks.
The publishers were warned before publication that their treatment of this is wrong, but arrogance, snobbery, ego, power, money - all got in the way of common sense. Some tried to save them from the ensuing embarrassment, but they reap what they sow, and now deserve to be defamed.
Defamation proceedings however will not commence because their legal teams will simply advise that if it goes to court, the judge will dismiss the case because they chose to publish rubbish and defendants simply called them out on it, as is their democratic right.
If you wish to delve into projectile motion with quadratic drag
and do it properly, ask yourself the question how prepared are you to use out-of-syllabus methods more appropriate to this issue like
Euler method or
Runge-Kutta method
The Cambridge Extension 2 book simply says this: "solutions can only be found in one case, when the resistance is proportional to the velocity."
Perhaps now you understand why nesa has made it clear in the new syllabus that they won't be doing projectile motion with quadratic drag.