Competition math — in-game stage & study lens

First Principles includes a dedicated Competition math stage (near the end of level select) that uses y = a\ln(k(x-d)) + c on a shifted domain — the same natural logarithm family you use in AP Calculus, TMUA/MAT, and contest prep, but framed for inequalities, bounding, and “is the function bending the right way?”

This page is unofficial study context only — not affiliated with the MAA (AMC/AIME), UKMT, Oxford MAT, or any olympiad organiser. For real contests, use official syllabi, past papers, and coaches.


What “competition math” usually stresses

Theme Calculus link Game hook
Bounding & estimates Compare to tangents/secants; mean value mood (\ln) is concave: chord/tangent tricks are standard toolkit
AM–GM (arithmetic–geometric mean) Often proved via (\ln) or convexity Same “turn products into sums” spirit as (\sum \ln)
Smoothness & case splits Domain of (\ln), removable vs essential mood Stage stays on a safe branch of (\ln) so the graph is clean
Clever substitution Chain rule / change of variables Parallel to “replace (u) to simplify” in integrals

Why (\ln) for this stage

  • Concavity: (f’‘(x)<0) on ((0,\infty)) for (f(x)=\ln x) — Jensen’s inequality for concave functions (and the tangent line upper bound) shows up constantly in olympiad-style inequalities.
  • Derivative: (\frac{d}{dx}\ln x = \frac{1}{x}) — reciprocals and harmonic-flavored estimates appear in many discrete bounds.
  • Domain hygiene: (\ln) forces you to think where an expression is defined — a contest habit of checking positivity before taking logs.

The derivative-driven platform rule in the game is unchanged: where the sampled derivative is large enough, you tend to get platforms; where it is not, you may see gaps / hazards — you are still “walking on slopes.”


How this fits next to other docs

Resource Role
Math concepts Broad in-game curriculum index
AP Calculus BC — prep Syllabus-shaped BC map (includes (\ln), concavity, series)
AMC 10 & 12 — prep MAA AMC multiple-choice map (unofficial); algebra/geo/NT + graph bridges
TMUA — calculus / MAT — calculus UK admissions multiple-choice / reasoning pace
This page Contest style: bounds, concavity, (\ln) as a hub

In-game title

The sample lineup no longer dedicates a level to this ln run — use any natural-log stage in your own graphs or study (\ln) concavity here; Mandelbrot remains the final boss after the economics pair in Advanced & boss.


Unofficial · First Principles (proprietary) — for learning mood only.