dgn-math-problems / ANSWER_AUDIT.md
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Answer audit

Every printed answer in this dataset was checked against the problem it belongs to by a symbolic engine (SymPy). This file reports what was checked, what held, and what the printed books got wrong.

Totals

  • problems in the dataset: 12,554
  • rows in the scored verified config: 2,132
  • printed answers refuted by the engine (concrete counterexample): 60
  • printed answers refuted and replaced by a re-verified recomputation: 17
  • printed answers only suspected to be wrong (no concrete counterexample): 114
  • rows set aside as disputed (a third read of the page disagreed): 102
  • rows with no printed answer at all (no-gold): 5,848

By source

source rows verified corrected refuted suspected disputed unverifiable synthetic-verified synthetic-unverified no-gold
algebra_core 3,617 1,297 17 34 97 95 1,632 0 0 445
falin_algebra 2,346 538 0 7 5 6 1,421 0 0 369
gelfand_trig 255 0 0 0 0 0 5 0 0 250
kozko_params 1,131 39 0 15 8 0 417 0 0 652
ponarin_plane 879 0 0 0 0 0 10 0 0 869
prasolov_planimetry 2,056 2 0 0 3 0 191 0 0 1,860
shabunin 1,750 48 0 4 1 1 293 0 0 1,403
synthetic 520 0 0 0 0 0 0 191 329 0

What each status means

status meaning
verified the answer was substituted back into the problem and the equation held
corrected the printed answer was refuted; it was replaced by a recomputed answer that the engine then re-verified
refuted the engine produced a concrete counterexample: the printed root was substituted back and failed, the printed tuple satisfies no equation of the system, or the printed interval misses a point that satisfies the inequality. The printed answer is demonstrably wrong.
suspected the recomputed answer differs from the printed one, but no concrete counterexample was found. A difference in a radical's scope or in a notational convention can produce this. These are not counted as book errors.
disputed a third independent read of the scanned page disagreed with the bulk transcription, so the row is not trusted
unverifiable the printed answer exists but is outside the reach of automatic checking - word problems, open-ended proofs, answers that depend on a figure
no-gold the source page carries no printed answer for this problem
synthetic-verified generated template; the printed statement was parsed, solved and compared with the printed answer
synthetic-unverified generated template; the answer is a derived quantity (a remainder, a sum of coefficients, ...) that no engine could re-check from the printed statement, so the row is published but not scored

Neither unverifiable, suspected, disputed nor no-gold means the answer is wrong. They mean nobody checked it, or that the check was inconclusive. The verified config is the honest scored split: every item in it has been checked by a symbolic engine.

How the checking works

problem type check
equation every printed root is substituted back into the equation; a solution family is checked at several integer values of its parameter
system of equations every ordering of the printed tuple is substituted into every equation
inequality the endpoints of the printed interval are evaluated exactly, and a grid of sample points is masked against the inequality
identity (prove that A = B) both sides are compared numerically at a grid of sample points
simplify the expression is evaluated numerically and compared with the printed result
limit / integral the expression is evaluated symbolically with SymPy
extremum (the greatest value is ...) a grid over the stated domain is searched for a counterexample to the claimed bound

Answers printed in degrees are converted to radians before checking, and degrees-minutes-seconds (3^\circ45') are parsed as 3.75 degrees.

Answers that were refuted and replaced

id printed answer recomputed answer
algebra_core.2.343 see the book x = - 2 \sqrt{3}
algebra_core.2.356 see the book x = - \sqrt{2}; x = \sqrt{2}
algebra_core.5.037 see the book x = - \frac{5 \pi}{6}; x = - \frac{4 \pi}{5}; x = - \frac{3 \pi}{5}; x = - \frac{\pi}{2}; x = - \frac{2 \pi}{5}; x = - \frac{\pi}{5}; x = - \frac{\pi}{6}; x = 0; x = \frac{\pi}{6}; x = \frac{\pi}{5}; x = \frac{2 \pi}{5}; x = \frac{\pi}{2}; x = \frac{3 \pi}{5}; x = \frac{4 \pi}{5}; x = \frac{5 \pi}{6}; x = \pi
algebra_core.5.107 see the book x = - \frac{\pi}{4}; x = \frac{3 \pi}{4}
algebra_core.5.123 see the book x = \operatorname{atan}{\left(\frac{1}{5} \right)}; x = \frac{\pi}{4}
algebra_core.5.162 see the book x = 0; x = \frac{2 \pi}{3}
algebra_core.5.217 see the book x = - \operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{5}}{2} \right)}; x = - \frac{\pi}{8}; x = - \operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{5}}{2} \right)}; x = \frac{3 \pi}{8}
algebra_core.5.232 see the book x = - \operatorname{atan}{\left(\frac{1}{5} + \frac{\sqrt{26}}{5} \right)}; x = - \frac{\pi}{8}; x = - \operatorname{atan}{\left(\frac{1}{5} - \frac{\sqrt{26}}{5} \right)}; x = \frac{3 \pi}{8}
algebra_core.5.413 see the book x = 0; x = \pi
algebra_core.5.421 see the book x = - \frac{\pi}{4}
algebra_core.7.038 see the book x = \frac{1}{100}; x = 100
algebra_core.7.039 see the book x = \frac{1}{10}; x = 1000
algebra_core.7.096 see the book x = \left(\frac{3^{\frac{2}{3}}}{3}\right)^{\frac{\sqrt[3]{3} \left(- \left(9 + \sqrt{105}\right)^{\frac{2}{3}} + 2 \sqrt[3]{3}\right)}{\sqrt[3]{9 + \sqrt{105}}}}
algebra_core.7.242 see the book x = \frac{1}{10}; x = \sqrt{10}; x = 100
algebra_core.7.243 see the book x = \frac{1}{1000}; x = 1; x = 10
algebra_core.7.250 see the book x = \frac{2^{\frac{2}{5}}}{8}; x = 1; x = 4
algebra_core.10.122 see the book x = \frac{9}{2}; x = 6

Printed answers the engine refuted

These are printed answers that do not hold: the engine produced a concrete counterexample. They are excluded from the verified config because no model can be scored correct on them.

id source printed answer what the engine found
algebra_core.1.202 algebra_core \sqrt{mn} the printed page was read at 800 dpi and the printed answer was refuted exactly - third read of the page disag …
algebra_core.1.206 algebra_core \frac{a(a+1)}{2a+1} the printed page was read at 800 dpi and the printed answer was refuted exactly - third read of the page disag …
algebra_core.2.068 algebra_core (-4;24);\ (-6;-2) three independent reads agree on the statement and the printed answer
algebra_core.2.169 algebra_core x_1=0;\ x_2=4. claimed solution 'x=4' fails the equation
algebra_core.2.205 algebra_core (2;1),\ (6;-3),\ \left(6+2\sqrt{3};-2-2\sqrt{3}\right),\ … three independent reads agree on the statement and the printed answer - error of the book: the printed answer …
algebra_core.2.240 algebra_core (10;1),\ \left(-21/2;53/12\right) three independent reads agree on the statement and the printed answer
algebra_core.2.243 algebra_core (1;4),(4;1),(-1;-4),(-4;-1) three independent reads agree on the statement and the printed answer
algebra_core.5.002 algebra_core x_1=35^\circ+120^\circ\cdot k,\quad x_2=55^\circ+120^\circ … three independent reads agree on the statement and the printed answer
algebra_core.5.039 algebra_core x_1=\frac{\pi k}{5},\ x_2=\frac{\pi}{8}(4k+3). three independent reads agree on the statement and the printed answer
algebra_core.5.121 algebra_core z_1=2\arctan3+2\pi k,\quad z_2=-2\arctan7+2\pi k three independent reads agree on the statement and the printed answer
algebra_core.5.147 algebra_core x=\frac{\pi}{12}(6k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.152 algebra_core x_1=\pi k,\quad x_2=(-1)^k\frac{k\pi}{6}+\frac{\pi k}{2} claimed solution 'x=(-1)^k\frac{k\pi}{6}+\frac{\pi k}{2}' fails the equation
algebra_core.5.174 algebra_core t=\frac{\pi}{2}(4k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.176 algebra_core x_1=\frac{\pi}{6}+\pi k;\quad x_2=(-1)^k\frac{\pi}{8}+\frac … three independent reads agree on the statement and the printed answer
algebra_core.5.177 algebra_core x=(-1)^k\frac{\pi}{3}+\pi k claimed solution 'x=(-1)^k\frac{\pi}{3}+\pi k' fails the equation
algebra_core.5.221 algebra_core x_1=-\frac{\pi}{16}(4k+1),\quad x_2=-\frac{1}{4}\arctan … three independent reads agree on the statement and the printed answer
algebra_core.5.227 algebra_core t=\arctan\frac{4}{5}+2\pi k three independent reads agree on the statement and the printed answer
algebra_core.5.259 algebra_core x=-\frac{\pi}{8}(4k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.269 algebra_core x=-\frac{\pi}{4}(4k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.334 algebra_core t=-\frac{\pi}{4}(4k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.344 algebra_core t=-\frac{\pi}{4}(4k-1) claimed solution 't=-\frac{\pi}{4}(4k-1)' fails the equation
algebra_core.5.348 algebra_core t=(-1)^k\frac{k\pi}{6}+\pi k three independent reads agree on the statement and the printed answer
algebra_core.5.445 algebra_core t=-\frac{\pi}{4}(4k+1) three independent reads agree on the statement and the printed answer
algebra_core.5.472 algebra_core t_1=\frac{\pi}{4}(8k+1),\quad t_2=-\arctan3+\pi(2k+1) three independent reads agree on the statement and the printed answer
algebra_core.7.151 algebra_core (9; 16) no assignment of the printed tuple (9; 16) satisfies the system
algebra_core.7.160 algebra_core (3; 27) three independent reads agree on the statement and the printed answer
algebra_core.7.263 algebra_core x_1=1/8,\ x_2=8. claimed solution 'x=1/8' fails the equation
algebra_core.8.026 algebra_core (-1,\infty) three independent reads agree on the statement and the printed answer
algebra_core.8.238 algebra_core (-\infty,-2]\cup[-1,(\sqrt{13}-1)/6) three independent reads agree on the statement and the printed answer
algebra_core.8.276 algebra_core (\sqrt[5]{5},5) the printed page was read at 800 dpi and the printed answer was refuted exactly - third read of the page disag …
algebra_core.8.283 algebra_core x=3 claimed integer 3 gives F=-1.2910247, which violates the inequality
algebra_core.10.012 algebra_core (-3,2)\cup(2,3) three independent reads agree on the statement and the printed answer
algebra_core.10.166 algebra_core (-4,0)\cup(0,4) three independent reads agree on the statement and the printed answer
algebra_core.11.246 algebra_core -\frac{1}{3} third read of the page corrected the row
falin_algebra.777 falin_algebra -\frac{19}{4}<x<-4 the printed page was read at 400 dpi and the printed answer was refuted exactly - x=-2.375 satisfies the inequ …
falin_algebra.788 falin_algebra -1 < x < -\frac{5}{6}. the printed page was read at 400 dpi and the printed answer was refuted exactly - the book's answer excludes t …
falin_algebra.926 falin_algebra [-18;-3] \cup (0;2). the printed page was read at 400 dpi and the printed answer was refuted exactly - the book's answer includes t …
falin_algebra.p370.598 falin_algebra (-\infty;\, -\tfrac{5+\sqrt{21}}{2}) \cup (\tfrac{-5+\sqrt … claimed point x=-5.79129 gives F=961.17, which violates the inequality
falin_algebra.p384.965 falin_algebra (2 - \log_2^2 3;\, 2] claimed endpoint 2 gives F=8.1307683, which violates the inequality
falin_algebra.p390.1020 falin_algebra (-1; 2] claimed point x=-0.85 gives F=-2.2992, which violates the inequality
falin_algebra.p544.2176 falin_algebra 2 \leq a \leq 2 + 2\sqrt{2}. claimed endpoint 4.82843 gives F=1.8284271, which violates the inequality
shabunin.p183.Example 3 shabunin (1;2), (-1;0) no assignment of the printed tuple (-1; 0) satisfies the system
shabunin.p190.Example 2 shabunin (1;2;3),\ (-1;-2;-3) no assignment of the printed tuple (-1; -2; -3) satisfies the system
shabunin.p194.Пример 8 shabunin (2;\sqrt[3]{3}; \sqrt[3]{9}),\ \left(\frac{1}{\sqrt[3]{2}}; … no assignment of the printed tuple (\frac{1}{\sqrt[3]{2}}; -\sqrt[3]{\frac{9}{2}}; \sqrt[3]{\frac{3}{2}} …
shabunin.p222.Пример 2 shabunin (1; 3); \left(\frac{9}{4}; 4\right) no assignment of the printed tuple (\frac{9}{4}; 4\right) satisfies the system
kozko_params.p163.3 kozko_params 0 < x \leqslant 1/2;\ x \geqslant \log_2 3 claimed point x=2.58496 gives F=-24.8292, which violates the inequality
kozko_params.2003-2-3 kozko_params [3/7; 1) \cup (3; +\infty) claimed endpoint 0.428571 gives F=-1.1818182, which violates the inequality
kozko_params.p176.Задача 3 kozko_params [(-1-2\sqrt{29})/5;\,2] claimed point x=-2.81962 gives F=0.68419, which violates the inequality
kozko_params.p195.3 kozko_params \left\{\left(-\frac{1}{2}; \log_9 \frac{9} … no assignment of the printed tuple (\log_4 \frac{4}{3}; -\frac{1}{2}\right) satisfies the system
kozko_params.p237.7 kozko_params \left(\dfrac{\pi}{4}+2\pi m;\ \dfrac{3\pi}{4}+2\pi k … no assignment of the printed tuple (-\dfrac{\pi}{4}+2\pi m; \ \dfrac{\pi}{4}+2\pi k …
kozko_params.ВАРИАНТ 2004 (июль), социологический факультет, 1 kozko_params [-5; -3]. claimed endpoint -5 gives F=0.66666667, which violates the inequality
kozko_params.p271.2 kozko_params (-\infty; 1/4] claimed point x=-0.75 gives F=0.275412, which violates the inequality
kozko_params.p274.1 kozko_params 2 claimed integer 2 gives F=9, which violates the inequality
kozko_params.ВАРИАНТ 2005 (июль), географический факультет, 1 kozko_params 1. (x;y) = (-\pi/2 \pm \pi/3 + 2\pi k;\ 2\pi m),\ k,m \in … no assignment of the printed tuple (3\pi+4) satisfies the system
kozko_params.p280.4 kozko_params (-\infty;\, 1-\sqrt{14}] \cup [-\sqrt{17}/3;\, -2) \cup (1; … x=-2.19 satisfies the inequality but is missing from the book's answer
kozko_params.p281.1 kozko_params x=-2 claimed solution 'x=-2' fails the equation
kozko_params.p289.2 kozko_params (-\infty;2] claimed endpoint 2 gives F=-0.17157288, which violates the inequality
kozko_params.p290.2 kozko_params (-\infty; 0] claimed point x=-10 gives F=0.00537474, which violates the inequality
kozko_params.Задача 1 (Вариант 2006, апрель) kozko_params [-2; (7+\sqrt{21})/21) claimed point x=6.14955 gives F=-0.294805, which violates the inequality
kozko_params.p293.Задача 2 kozko_params [-3; (5+\sqrt{21})/2) claimed endpoint -3 gives F=-5, which violates the inequality

Printed answers only suspected to be wrong

For these rows the recomputed answer differs from the printed one, but the engine could not produce a concrete counterexample. The difference can come from how the radical scope or a notational convention was read in the scan, so these are not counted as book errors and are kept out of the scored split as well.

id source printed answer what the engine found
algebra_core.1.004 algebra_core 0.04 numeric difference over 2 point(s) - reported as suspected, not as a refutation: the difference can come from …
algebra_core.1.023 algebra_core 0.5a^3(a-1) the printed answer is contradicted at a=3: the expression is exactly 27/4, the printed answer gives 27 - repor …
algebra_core.1.027 algebra_core -4 the printed answer is contradicted at a=1, b=4: the expression is exactly (-27649 + 242(1/3) + 5762**(2/3) …
algebra_core.1.028 algebra_core \frac{2}{\sqrt[3]{r^2}}\left(r^2-\sqrt{r^4-16}\right) the printed answer is contradicted at r=2: the expression is exactly 2**(1/3), the printed answer gives 42*( …
algebra_core.1.039 algebra_core y^2 the printed answer is contradicted at y=1: the expression is exactly (30**(1/10)(sqrt(2) + 3) + 6sqrt(2) + 8 …
algebra_core.1.041 algebra_core -4 the printed answer is contradicted at t=1: the expression is exactly 152/25, the printed answer gives -4 - rep …
algebra_core.1.050 algebra_core 2\sqrt[6]{a^5/a} the printed answer is contradicted at a=1: the expression is exactly 2**(11/12)/2, the printed answer gives 2 …
algebra_core.1.053 algebra_core \sqrt{6x} the printed answer is contradicted at x=3: the expression is exactly 0, the printed answer gives 3*sqrt(2) - r …
algebra_core.1.054 algebra_core \sqrt[3]{20x} the printed answer is contradicted at x=1: the expression is exactly -2sqrt(3) + 2sqrt(2)(4sqrt(6) + 11)** …
algebra_core.1.056 algebra_core 1/\sqrt[12]{a^2b} the printed answer is contradicted at a=1, b=2: the expression is exactly 1/2, the printed answer gives 2**(11 …
algebra_core.1.059 algebra_core -1 the printed answer is contradicted at a=2: the expression is exactly -2**(1/4) - 1 - 2**(3/4)/2 + sqrt(sqrt(2) …
algebra_core.1.061 algebra_core -(\sqrt[4]{x}-\sqrt[4]{y}) the printed answer is contradicted at x=1, y=2: the expression is exactly 3*(1 - sqrt(2))/(-3 + 2**(1/4) + 2** …
algebra_core.1.063 algebra_core a^{1/3}+b^{1/3} the printed answer is contradicted at a=1, b=2: the expression is exactly (-22(2/3) + 1 + 22**(1/3))/(1 - …
algebra_core.1.065 algebra_core (\sqrt{m}-\sqrt{n})/m the printed answer is contradicted at m=1, n=2: the expression is exactly -sqrt(sqrt(5)/4 + 3/4), the printed …
algebra_core.1.067 algebra_core 1 the printed answer is contradicted at : the expression is exactly (-sqrt(5) + 2*sqrt(6))/(-sqrt(3) + sqrt(2)), …
algebra_core.1.068 algebra_core \frac{1}{a\left(\sqrt[m]{a}-\sqrt[n]{a}\right)} the printed answer is contradicted at a=2, m=1, n=2: the expression is exactly 5*sqrt(2)/14 + 4/7, the printed …
algebra_core.1.069 algebra_core 6 the printed answer is contradicted at : the expression is exactly (-18sqrt(5) - 12(1/3) + 30sqrt(3))/(-3*s …
algebra_core.1.073 algebra_core -\sqrt{ac} the printed answer is contradicted at a=1, b=1, c=2: the expression is exactly 2**(190/213)3(308/639)5(4 …
algebra_core.1.077 algebra_core \frac{x^{1/3}+y^{1/3}}{\sqrt[6]{x^3y^2}} the printed answer is contradicted at x=2, y=1: the expression is exactly (-2**(1/6) - 1 + 2**(2/3) + 2**(5/6) …
algebra_core.1.080 algebra_core 0 the printed answer is contradicted at m=1, n=1: the expression is exactly -2, the printed answer gives 0 - rep …
algebra_core.1.083 algebra_core 5 the printed answer is contradicted at b=1, c=1, a=1/25: the expression is exactly 5sqrt(51)(sqrt(101) + 20)/ …
algebra_core.1.086 algebra_core \frac{1}{\sqrt{a}+\sqrt{2}} the printed answer is contradicted at a=1: the expression is exactly -1/2 + 2*sqrt(2)/3, the printed answer gi …
algebra_core.1.087 algebra_core -3n(m+p) the printed answer is contradicted at m=1, n=1, p=1: the expression is exactly (sqrt(6) + 23(1/3))(-2**(1/ …
algebra_core.1.089 algebra_core (1-a)/\sqrt{a} the printed answer is contradicted at a=2: the expression is exactly sqrt(3)*(-4 + sqrt(2))/24, the printed an …
algebra_core.1.098 algebra_core \sqrt[3]{x+y}-\sqrt[3]{x-y} the printed answer is contradicted at x=2, y=1: the expression is exactly 2**(1/3), the printed answer gives - …
algebra_core.1.101 algebra_core 2 the printed answer is contradicted at x=1: the expression is exactly 2/3 - 2*sqrt(2)/3, the printed answer giv …
algebra_core.1.107 algebra_core a/2 the printed answer is contradicted at a=1, b=2, p=3: the expression is exactly sqrt(2)/(-22(5/6) - 22**(1/ …
algebra_core.1.116 algebra_core 1/m^2 the printed answer is contradicted at m=1, n=2: the expression is exactly sqrt(2)/(-62(3/4) - 82**(1/4) + …
algebra_core.1.117 algebra_core -a^2 the printed answer is contradicted at a=1, b=2: the expression is exactly -2**(3/4)/2, the printed answer give …
algebra_core.1.120 algebra_core 3/5 the printed answer is contradicted at : the expression is exactly (32(1/3)7(1/4) + 602(1/3))/(22**(1 …
algebra_core.1.121 algebra_core 31/3 the printed answer is contradicted at : the expression is exactly 2**(1/3)(206**(1/3) + 63)/(2*(6**(2/3) + 1 …
algebra_core.1.122 algebra_core \sqrt[12]{32} the printed answer is contradicted at : the expression is exactly -32(7/12) + 22**(1/6) + 22*(11/12), th …
algebra_core.1.123 algebra_core 0.1 the printed answer is contradicted at : the expression is exactly -36sqrt(5) - 23**(1/4)sqrt(5) + 8sqrt(30 …
algebra_core.1.124 algebra_core 0 the printed answer is contradicted at : the expression is exactly 3**(1/3)(-27sqrt(2)3(1/3) - 112**(1/6) …
algebra_core.1.142 algebra_core -\frac{\sqrt{6}}{2} the printed answer is contradicted at x=sqrt(6): the expression is exactly 0, the printed answer gives -sqrt(6 …
algebra_core.1.160 algebra_core \frac{1}{z+2} the printed answer is contradicted at x=1, z=2: the expression is exactly 1/3, the printed answer gives 1/4 - …
algebra_core.1.173 algebra_core \frac{x+y}{2} the printed answer is contradicted at x=1, y=2: the expression is exactly 38/17 + 61*sqrt(2)/34, the printed a …
algebra_core.1.176 algebra_core \frac{m-8}{2} the printed answer is contradicted at m=9: the expression is exactly 144*sqrt(5) + 322, the printed answer giv …
algebra_core.1.180 algebra_core \frac{1}{a(3a+b)} the printed answer is contradicted at a=1, b=2: the expression is exactly 2/5 - 22*(1/6)/5, the printed answ …
algebra_core.1.184 algebra_core \frac{1}{x-\sqrt{2x+1}} the printed answer is contradicted at x=2: the expression is exactly sqrt(6)/5 + 6/5, the printed answer gives …
algebra_core.1.186 algebra_core \sqrt{x^3}-\sqrt{y^3} the printed answer is contradicted at x=1, y=1: the expression is exactly 1/2, the printed answer gives 0 - re …
algebra_core.1.194 algebra_core x^2\sqrt[3]{y^1} the printed answer is contradicted at x=1, y=1: the expression is exactly -sqrt(3)(4sqrt(3) + 7)**(1/6) + 2* …
algebra_core.1.197 algebra_core \frac{{}^{4}\!\sqrt a}{6} the printed answer is contradicted at a=2: the expression is exactly 32(1/12)(-(2 - sqrt(2))(1/6) + 2( …
algebra_core.1.201 algebra_core 1/(ab) the printed answer is contradicted at a=1, b=2: the expression is exactly (2**(1/3)/16 + 1/2)/(1 + 2**(1/4)), …
algebra_core.1.222 algebra_core -\frac{\sqrt{x-2}}{x+2} the printed answer is contradicted at x=3: the expression is exactly -sqrt(5)/5, the printed answer gives -1/5 …
algebra_core.1.224 algebra_core \sqrt{a}\left(\sqrt{2a+1}-\sqrt{a}\right) the printed answer is contradicted at a=1: the expression is exactly 1/2 + sqrt(3)/2, the printed answer gives …
algebra_core.1.226 algebra_core 2.4 the printed answer is contradicted at c=1, a=24/5, b=6/5: the expression is exactly 12*sqrt(163112586)/298741 …
algebra_core.1.231 algebra_core \sqrt{p^2-q^2}\sqrt{p} the printed answer is contradicted at p=2, q=1: the expression is exactly 15 - 2*sqrt(6), the printed answer g …
algebra_core.1.233 algebra_core \frac{4}{9} the printed answer is contradicted at b=1, a=9/4: the expression is exactly 2sqrt(-3960sqrt(2) + 3718*sqrt(3 …
algebra_core.1.236 algebra_core \sqrt[3]{p-q} the printed answer is contradicted at p=3, q=1: the expression is exactly 2**(7/8)/2, the printed answer gives …
algebra_core.1.237 algebra_core 2 the printed answer is contradicted at m=3: the expression is exactly (-2*(4 - 3**(2/3))(15(2/3) + 10) + 55 …
algebra_core.1.238 algebra_core 1 the printed answer is contradicted at a=1, b=2: the expression is exactly (1 + sqrt(2))(4/3)/(2*2(5/6) + 3 …
algebra_core.1.240 algebra_core \sqrt{a}(a+4b) the printed answer is contradicted at a=1, b=1: the expression is exactly sqrt(5)/5, the printed answer gives …
algebra_core.1.241 algebra_core 1 the printed answer is contradicted at p=1, q=2: the expression is exactly 4, the printed answer gives 1 - repo …
algebra_core.1.324 algebra_core b-4a if a\in[0,\sqrt{2}); 2(a-1)^2 if a\in[\sqrt{2},+\infty) the printed value '2(a-1)^2' does not hold at a=3, where it is the only case that applies - reported as suspec …
algebra_core.1.329 algebra_core -x if x\in(0,1); x if x\in(1,\infty) the printed value '-x' does not hold at x=1/2, where it is the only case that applies - reported as suspected, …
algebra_core.1.330 algebra_core \frac{x-1}{x} if x\in(-\infty,0)\cup[1,\infty); \frac{1-x} … the printed value '\frac{x-1}{x}' does not hold at x=2, where it is the only case that applies - reported as …
algebra_core.2.368 algebra_core x=2 the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.4.080 algebra_core \tan\frac{m+n}{2}\alpha the printed answer is contradicted at alpha=1, m=1, n=2: the expression is exactly (-cos(1) + cos(2))/(-sin(2) …
algebra_core.4.117 algebra_core \tan^6\alpha numeric difference over 2 point(s) - reported as suspected, not as a refutation: the difference can come from …
algebra_core.4.145 algebra_core 2\sqrt2\sin^2\alpha\cos\left(\frac\pi4+2\alpha\right) the printed answer is contradicted at alpha=1: the expression is exactly -sqrt(-sin(1) + tan(1)) + sqrt(sin(1) …
algebra_core.4.241 algebra_core \displaystyle -\frac12\sin2\alpha the printed answer is contradicted at alpha=1: the expression is exactly sqrt(-cos(2))/sqrt(-cot(1)**2 + tan(1 …
algebra_core.4.248 algebra_core \displaystyle \sin4\alpha\cos^{-2}4\alpha the printed answer is contradicted at alpha=1, x=2: the expression is exactly (sin(24) + sin(8))/(cos(16) + 1) …
algebra_core.4.264 algebra_core \tan5\alpha the printed answer is contradicted at alpha=1, x=2: the expression is exactly tan(10), the printed answer give …
algebra_core.4.265 algebra_core \sin3\alpha the printed answer is contradicted at alpha=1, x=2: the expression is exactly sin(6), the printed answer gives …
algebra_core.4.266 algebra_core \cos3\alpha the printed answer is contradicted at alpha=1, x=2: the expression is exactly cos(6), the printed answer gives …
algebra_core.4.270 algebra_core 2\sin2\alpha the printed answer is contradicted at alpha=1, x=1: the expression is exactly (-sin(pi/4 + 2) + sin(pi/4 + 6)) …
algebra_core.4.272 algebra_core \cot\left(\alpha-\frac{\pi}{4}\right) numeric difference over 2 point(s) - reported as suspected, not as a refutation: the difference can come from …
algebra_core.4.291 algebra_core -2\sin\frac{\alpha}{4} the printed answer is contradicted at alpha=1: the expression is exactly -sqrt(1 - sin(1/2)) + sqrt(sin(1/2) + …
algebra_core.4.300 algebra_core \frac{4\sin^2\left(\frac{\pi}{4}-4\alpha\right)} … the printed answer is contradicted at alpha=1: the expression is exactly -tan(4) - cot(4) + 2, the printed ans …
algebra_core.4.381 algebra_core a) (\cos 2\alpha)_1=-3/5; b) (\cos 2\alpha)_2=4/5 sides differ numerically - reported as suspected, not as a refutation: the difference can come from the readin …
algebra_core.4.382 algebra_core a) 4/5; b) 3/5 sides differ numerically - reported as suspected, not as a refutation: the difference can come from the readin …
algebra_core.4.412 algebra_core -\cos^32x the printed answer is contradicted at x=1: the expression is exactly -4*sin(1)*6 - 1 - 4cos(1)*6 + 4cos(1) …
algebra_core.4.449 algebra_core (1 - a^2)/(2a) numeric difference over 2 point(s) - reported as suspected, not as a refutation: the difference can come from …
algebra_core.4.488 algebra_core A=B=|\cos\alpha\cos\beta\cos\gamma| the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.154 algebra_core x = \frac{2\pi}{3}(3k \pm 1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.155 algebra_core x_1=\frac{\pi}{2}(2k+1),\quad x_2=(-1)^k\frac{\pi}{6}+\pi k the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.156 algebra_core t_1=(-1)^k\frac{\pi}{6}+\pi k,\quad t_2=\frac{\pi}{2}(4k+1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.158 algebra_core x=\frac{\pi}{6}(6k\pm1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.186 algebra_core x_1=2\pi k,\ x_2=\frac{\pi}{2}(2k+1),\ x_3=\frac{\pi}{4}(4k- … the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.197 algebra_core x_1=\frac{\pi k}{3}; x_2=\frac{\pi}{12}(2k+1). the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.263 algebra_core t=\frac{\pi}{3}(3k\pm1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.301 algebra_core t_1 = 360^\circ \cdot k; \quad t_2 = 90^\circ (4k+1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.302 algebra_core t_1=90^\circ\cdot k;\quad t_2=\pm15^\circ+90^\circ\cdot k the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.311 algebra_core x=2\pi k. the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.337 algebra_core t=\pi k the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.467 algebra_core x=\frac{\pi}{2}(4k+1) the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.5.490 algebra_core x_1=\arccos\left(\sqrt5-2\right)+2\pi k,\quad x_2=\pi(2k+1). the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.6.088 algebra_core \approx 0.95 the printed answer is contradicted at approx=1, x=-1/20: the expression is exactly 160000/168421, the printed …
algebra_core.7.045 algebra_core 890 the printed answer is contradicted at : the expression is exactly sqrt(7) + 625 + 531441**(log(3)/log(6)), the …
algebra_core.8.055 algebra_core [0, 4). the book's answer excludes the upper endpoint 4, but it satisfies the inequality - reported as suspected, not …
algebra_core.8.148 algebra_core [-3,-\sqrt{6})\cup(-\sqrt{6},-2]\cup[2,\sqrt{6})\cup(\sqrt … the book's answer includes the lower endpoint -3, where equality holds - reported as suspected, not as a refut …
algebra_core.8.185 algebra_core (a^4,a^{-1}) if 0<a<1; (a^{-1},a^4) if a>1 the book's answer excludes the upper endpoint 2, but it satisfies the inequality (for a=1/2) - reported as sus …
algebra_core.10.093 algebra_core (\sqrt{x}-\sqrt{y})(\sqrt{x}-2\sqrt{y}) the printed answer is contradicted at x=1, y=1: the expression is exactly 2, the printed answer gives 0 - repo …
algebra_core.10.145 algebra_core x is an integer. the two sides of the identity differ at every tested point - reported as suspected, not as a refutation: the d …
algebra_core.11.078 algebra_core a>4 the book's answer excludes the lower endpoint 4, but it satisfies the inequality - reported as suspected, not …
algebra_core.11.252 algebra_core 0.5\ln 2-1.5 numeric difference over 2 point(s) - reported as suspected, not as a refutation: the difference can come from …
falin_algebra.269 falin_algebra x = \dfrac{-3 + \sqrt{17}}{2}. sides differ numerically
falin_algebra.540 falin_algebra \{\tfrac{2}{5};\, 10\}. the two sides of the identity differ at every tested point
falin_algebra.907 falin_algebra x>\sqrt{3} the book's answer excludes the lower endpoint 1.73205, but it satisfies the inequality
falin_algebra.1023 falin_algebra 4017 integer 4014 satisfies the inequality but is not listed
falin_algebra.p446.1397 falin_algebra **Answer:** \emptyset. the two sides of the identity differ at every tested point
shabunin.p288.23 shabunin x > -\frac{1}{2} the book's answer excludes the lower endpoint -0.5, but it satisfies the inequality
kozko_params.p18.30 kozko_params a \in (0; 1/54) the book's answer excludes the upper endpoint 0.0185185, but it satisfies the inequality
kozko_params.p172.6 kozko_params (1; 18 - 12\sqrt{2}] a=500.545 satisfies the inequality but is missing from the book's answer - reported as suspected: the printed …
kozko_params.p173.6 kozko_params (1; 8 - 4\sqrt{3}] a=500.565 satisfies the inequality but is missing from the book's answer - reported as suspected: the printed …
kozko_params.p188.1 kozko_params [-7; -2) \cup (-2; -1]. the book's answer excludes the upper endpoint -2, but it satisfies the inequality
kozko_params.198_2 kozko_params 207 the printed answer is contradicted at x=1, y=1: the expression is exactly 2, the printed answer gives 207
kozko_params.p263.3 kozko_params x \in [1; 2) \cup (2; \sqrt{5}) the book's answer excludes the upper endpoint 2.23607, but it satisfies the inequality
kozko_params.p266.Задача 1 kozko_params (0;\, (5 - \sqrt{17})/2) the book's answer excludes the upper endpoint 0.438447, but it satisfies the inequality
kozko_params.p266.Задача 5 kozko_params a \in [\pi/2;\, 3\pi/2 - 3] \cup (5\pi/2 - 6;\, 7\pi/2 - 9] the book's answer excludes the lower endpoint 20.5708, but it satisfies the inequality
prasolov_planimetry.6.37 prasolov_planimetry AB \cdot CD + AD \cdot BC = AC \cdot BD the two sides of the identity differ at every tested point
prasolov_planimetry.13.31 prasolov_planimetry \boldsymbol{e}_1 \sin\alpha + \boldsymbol{e}_2 \sin\beta + … the two sides of the identity differ at every tested point
prasolov_planimetry.31.45 prasolov_planimetry a + c = 0 the two sides of the identity differ at every tested point

Reproducing the audit

python verify_all3.py 12 dataset/core_math_dataset_v2.jsonl v15   # the core book
python reverify_books2.py bookv15                                   # the additional books
python build_benchmark.py                                            # assemble + split
python audit_pairing.py hf_dataset/benchmark_full.jsonl              # question/answer integrity

The verification engine is verify3.py; verify.py holds the individual checkers and verify2.py the newer ones (inequalities, limits, integrals, factors).

Errors of the books that the engine cannot see

These are errors of the source books, found by reading the printed page. Two kinds occur: a wrong printed answer, which the symbolic engine does not reach because the exercise has several parts and a list of answers cannot be checked as a whole, and a misprinted statement, where the book prints a statement that does not match its own printed answer.

id kind part what the book prints what is correct why
gelfand_trig.p158.26.6 wrong printed answer (d) \left(\dfrac{\sqrt{3}}{3}; 1\right] \left(\dfrac{\sqrt{3}}{2}; 1\right] the exercise asks to solve arccos x < pi/6, whose solution is x in (cos(pi/6), 1] = (sqrt(3)/2, 1]; the book prints (sqrt(3)/3, 1]
algebra_core.2.205 misprinted statement second equation of the system \begin{cases}x+y+\frac{x^2}{y^2}=7,\\ \frac{(x-y)x^2}{y^2}=12.\end{cases} \begin{cases}x+y+\frac{x^2}{y^2}=7,\\ \frac{(x+y)x^2}{y^2}=12.\end{cases} the printed answer does not satisfy the printed second equation: (2; 1) gives (x-y)x^2/y^2 = 4, not 12, and (6; -3) gives 36, not 12. All four printed answers satisfy x+y+x^2/y^2 = 7 and (x+y)x^2/y^2 = 12 exactly, so the book misprinted x+y as x-y. The printed system as written has exactly one real solution, (1.3863205; -0.5580341), whose coordinates are roots of a quintic and are therefore certainly not the intended answer.
algebra_core.1.206 wrong printed answer \frac{a}{a+1} \frac{a(a+1)}{2a+1} the printed expression (a+1)/(2*cuberoot(sqrt(3)-sqrt(2))6throot(5+2sqrt(6)) + 1/a) equals a(a+1)/(2a+1), because 2cuberoot(sqrt(3)-sqrt(2))*6throot(5+2sqrt(6)) = 2 exactly; the difference between the printed answer and the true value is a^3/((a+1)(2a+1)), which is not an identity
algebra_core.1.202 wrong printed answer \sqrt{mn} the expression has no closed form in m and n; its value at m = 8, n = 1 is exactly 40/3, so the printed answer cannot be right. The cube root of mn is not the value either (it would be 2 at that point) the printed expression (cube root of m^2 + ncube root of m + n^2) * (cube root of m^4 - n^3 + n^2cube root of (m - mn)) / (mn^-1 + n - n^4m^-1 - n^2) does not have the square root of mn as its value. At m = 8 and n = 1 the expression is exactly 40/3, a rational number, while the printed answer is sqrt(8) = 2sqrt(2), an irrational number, so the two can never be equal. The denominator is not zero there (it is 63/8), so the point lies inside the domain of the expression. The first factor and the denominator do factor neatly - the first one is (m - n^3)/(cube root of m - cube root of n) and the denominator is (m + n^2)(m - n^3)/(m*n) - which is why the statement was read carefully before the answer was called wrong
algebra_core.8.276 wrong printed answer (\sqrt[3]{5},5) (\sqrt[5]{5},5) the printed answer is (cuberoot(5), 5) = (5^(1/3), 5), but the answer of the printed inequality log_x^2 sqrt(5) - log_x 5 sqrt(5) + 1,25 < 0 is (5^(1/5), 5). With t = log_x 5 the printed inequality becomes t^2/4 - 3t/2 + 5/4 < 0, i.e. (t-1)(t-5) < 0, so 1 < t < 5 and x = 5^(1/t) runs from 5^(1/5) to 5; the cube root 5^(1/3) is only an interior point of that interval, not its lower endpoint. The root index in the printed answer is a 3, not a 5: it was read from the page image at 800 dpi and the index glyph was compared pixel by pixel with the index of the cube root in 3sqrt35 printed on the same answer page; it matches the 3 far better than the 5 (IoU 0.61 against 0.51, and a 5 would have a horizontal top bar reaching the left edge and a narrow middle stem, neither of which the printed glyph has).
algebra_core.1.111 wrong printed answer 100 the expression is negative at the stated values a = 25/7 and x = 7/25; under the transcribed structure its value is exactly -31250*sqrt(7)/343 - 84/25 the exercise asks for the value of the printed expression at a = 3 4/7 = 25/7 and x = 0,28 = 7/25. There ax = 1, so the dominant term -10a sqrt(x) sqrt((a x^-1)^2) is exactly -31250sqrt(7)/343 (about -241.1), and the remaining terms are bounded by 229 and 3, so the value is negative in every faithful reading of the printed expression (eight readings were evaluated exactly: the transcribed structure gives -31250sqrt(7)/343 - 84/25, the structure in which the first group is printed as ( ... )^3 gives about -1.39*10^7). A positive printed answer of 100 is therefore impossible.
falin_algebra.777 wrong printed answer $-\frac{19}{4} < x < -4$ $\left(-\frac{11}{4};\, -2\right) \cup \left(-2;\, +\infty\right)$ the printed answer of log_{x+3}(1/2) > 1/2 lies entirely outside the domain of the logarithm, which needs x > -3 and x != -2. Solving the printed inequality gives x in (-11/4, -2) union (-2, +infinity): for 0 < x+3 < 1 the logarithm decreases, so 1/2 < (x+3)^(1/2) and x > -11/4, and for x+3 > 1 the inequality holds everywhere. The point x = -19/8 satisfies the inequality and is missing from the printed answer. The printed page 99 was read at 400 dpi and shows exactly -19/4 < x < -4.
falin_algebra.788 wrong printed answer $-1 < x < -\frac{5}{6}$ $-1 < x < \frac{1}{\sqrt[3]{36}} - 1$ the printed answer of log_6 log_{1/6th-root-of-6}(x+1) > 1 is too narrow. Writing u = log_{6^(-1/9)}(x+1), the condition is u > 6, and because the base is below 1 this gives 0 < x+1 < 6^(-2/3), so the solution is -1 < x < 6^(-2/3) - 1 = -0.6972.... The printed upper end -5/6 = -0.8333 excludes the whole stretch from -0.8333 to -0.6972; the point x = -0.8 satisfies the inequality (log_6 log_{6^(-1/9)}(0.2) = 1.166 > 1) and is missing from the printed answer. The printed page 100 was read at 400 dpi.
falin_algebra.926 wrong printed answer $[-18;-3] \cup (0;2)$ $[-18;-3) \cup (0;2)$ in sqrt((x^2+9x-162)/(x-2)) > x+9 equality holds at x = -3, because the radicand is 36 there and x+9 is 6 as well, so the strict inequality fails and -3 must not belong to the solution. The book closes the bracket at -3. The difference of the two sides is -x(x+3)(x+12)/(x-2), which changes sign exactly at -3. The printed page 116 was read at 400 dpi and shows the closed bracket.