How this is verified

Quadrature is AI-authored under an owner-designed verification system. There is no human-review gate on the mathematics by design — the verification system is the safeguard, and the build fails rather than ships when a claim does not hold.

Two honest axes

Machine-derived

The algebra solution, the calculus derivation, the proof that the two agree, the dimensional check, and the closed form the graphs run on are all produced and checked by SymPy. The proof is shown, not asserted — see the proof panel in any lesson.

Author-asserted

The physics modeling assumptions — g = −10 (a clean-arithmetic simplification of 9.81), "no air resistance," "point mass" — are an author's claims. They are disclosed, not discharged: you can check the math against SymPy, but you take the model on a textbook's footing. They never enter the derivation record.

What breaks the build

The three regimes

"Algebra is just calculus done" is only true for constant acceleration. Every topic declares which of three relationships it is: (1) algebra is calculus evaluated; (2) calculus does what algebra cannot (non-constant forces); (3) algebra-only. A learner always knows which one they are looking at.