I’ll admit I only graduated high school back in June and I already forgot how to do long division. I do know trig and the unit circle and whatnot pretty well though, and could do 51*51 in my head in about a minute.
That said, I don’t remember much from precalc, and barely passed it. At my school we had to write a full academic paper in our senior year and that took a lot of my energy. I also wasn’t allowed to drop any of the electives I took even though I didn’t need the credits, which meant I struggled a lot towards the end of senior year and many of my classes suffered. Somehow I still got a good GPA.
The E195 is a bit too small for mainline use, though a good aircraft otherwise. The others however I’m not sure are ready for the prime time.
The Comac has potential, it’s a completely new aircraft developed for the Chinese domestic market, I don’t know if it will be sold in the west though. One issue is that the aircraft market doesn’t lend itself to new players. Planes typically last 30 years give or take, so taking on a new type from an unproven manufacturer is a big risk. It could, however, be successful in the long term.
Irkut is majority owned by the Russian government, and given the war, is likely going to have issues. It has flown, but now they have to move to entirely homegrown parts, which will likely make the aircraft completely shit.
Speaking of, the Tupolev Tu-204. It is still in production, and since the war started it has begun to ramp up again. Unfortunately it still has significant problems. For an aircraft built today, it still uses a three person cockpit crew, and is very underpowered. It also has had nearly no changes since its introduction in 1989, and is way behind pretty much any aircraft of its size.
It’s worth considering how much room there is in the airliner market for more competitors. Since aircraft require a huge amount of R&D, you have to sell a lot of them to break even. So if there’s too many manufacturers vying for a finite market, it gets hard to find any RoI. This has happened a lot historically, it’s like streaming services except you can’t actually get anyone to buy duplicates and very rarely will anyone split their orders.