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Question 24440: Evaluate Every Coordinate Derivative at the Same Exact Rational Point

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0047-24440 · q-20261015-advance-20261113-r06-gradient-vector-0040

Original question and givens

Use dimension=2, raw polynomial terms=[[15, [2, 1]], [16, [0, 1]], [1, [0, 0]]], each [rational coefficient,ordered exponent vector]. Coefficients may be integers or [numerator,denominator]. Exponent/point arities equal the dimension. Combine equal monomials and remove zero coefficients before the canonical symbolic output. Coordinate order and the standard Euclidean basis/metric are fixed. Point=[15/1, 16/2]. Give (dimension, canonical_terms, point, coordinate_derivative_polynomials, gradient_values, certificate).

  • G001 — Use dimension=2, raw polynomial terms=[[15, [2, 1]], [16, [0, 1]], [1, [0, 0]]], each [rational coefficient,ordered exponent vector]. Coefficients may be integers or [numerator,denominator]. Exponent/point arities equal the dimension. Combine equal monomials and remove zero coefficients before the canonical symbolic output. Coordinate order and the standard Euclidean basis/metric are fixed. Point=[15/1, 16/2]. Give (dimension, canonical_terms, point, coordinate_derivative_polynomials, gradient_values, certificate).

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

source roles = [gradient-rational-point]

After

derived = [[dimension, canonical_terms, point, coordinate_derivative_polynomials, gradient_values, certificate]]

Conditions: none

List the source field order without JavaScript.Gradient boundary uses its original mode to choose6,8 or7 fields;no padding or answer-derived mode.

Step identifiers and dependencies

Rule: source_ordered_fields_without_JS · Uses: G001

S002 · calculation

Before

Gradient ORIGINAL monomial coefficient sum0 := sum(0, 15)

After

Gradient ORIGINAL monomial coefficient sum0 = 15

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · implies

Before

source roles = [0, 2, [2, 1], 15]

After

derived = [15]

Conditions: none

Combine only identical ordered exponent vectors;remove zeros after combining and keep fixed Euclidean coordinate order.

Step identifiers and dependencies

Rule: Gradient_original_term_position_and_exponent_arity · Uses: G001, S002

S004 · calculation

Before

Gradient ORIGINAL monomial coefficient sum1 := sum(0, 16)

After

Gradient ORIGINAL monomial coefficient sum1 = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · implies

Before

source roles = [1, 2, [0, 1], 16]

After

derived = [16]

Conditions: none

Combine only identical ordered exponent vectors;remove zeros after combining and keep fixed Euclidean coordinate order.

Step identifiers and dependencies

Rule: Gradient_original_term_position_and_exponent_arity · Uses: G001, S004

S006 · calculation

Before

Gradient ORIGINAL monomial coefficient sum2 := sum(0, 1)

After

Gradient ORIGINAL monomial coefficient sum2 = 1

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

source roles = [2, 2, [0, 0], 1]

After

derived = [1]

Conditions: none

Combine only identical ordered exponent vectors;remove zeros after combining and keep fixed Euclidean coordinate order.

Step identifiers and dependencies

Rule: Gradient_original_term_position_and_exponent_arity · Uses: G001, S006

S008 · implies

Before

source roles = [[[15, [2, 1]], [16, [0, 1]], [1, [0, 0]]]]

After

derived = [2, [[1, [0, 0]], [16, [0, 1]], [15, [2, 1]]]]

Conditions: none

Use source English canonical-exponent order,not numeric tuple order.Complete cancellation may yield an empty canonical list for the zero polynomial.

Step identifiers and dependencies

Rule: Gradient_canonical_nonzero_polynomial_terms_source_order · Uses: G001, S007

S009 · implies

Before

source roles = [0, 0, [0, 0], 1]

After

derived = [0]

Conditions: none

Exponent0 means derivative0 in this coordinate,without omitting other coordinates.

Step identifiers and dependencies

Rule: Gradient_constant_in_coordinate_derivative_zero · Uses: G001, S008

S010 · implies

Before

source roles = [0, 1, [0, 1], 16]

After

derived = [0]

Conditions: none

Exponent0 means derivative0 in this coordinate,without omitting other coordinates.

Step identifiers and dependencies

Rule: Gradient_constant_in_coordinate_derivative_zero · Uses: G001, S009

S011 · calculation

Before

Gradient axis0 term2 power-rule coefficient := mul(15, 2)

After

Gradient axis0 term2 power-rule coefficient = 30

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S010

S012 · calculation

Before

Gradient axis0 derivative combine2 := sum(0, 30)

After

Gradient axis0 derivative combine2 = 30

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · implies

Before

source roles = [0, 2, [2, 1], 15, 2]

After

derived = [[1, 1], 30]

Conditions: none

Hold the other variables fixed:the coefficient becomes ck and only this coordinate exponent decreases by1.

Step identifiers and dependencies

Rule: Gradient_coordinate_power_rule_ordered_exponents · Uses: G001, S012

S014 · implies

Before

source roles = [1, 0, [0, 0], 1]

After

derived = [0]

Conditions: none

Exponent0 means derivative0 in this coordinate,without omitting other coordinates.

Step identifiers and dependencies

Rule: Gradient_constant_in_coordinate_derivative_zero · Uses: G001, S013

S015 · calculation

Before

Gradient axis1 term1 power-rule coefficient := mul(16, 1)

After

Gradient axis1 term1 power-rule coefficient = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S014

S016 · calculation

Before

Gradient axis1 derivative combine1 := sum(0, 16)

After

Gradient axis1 derivative combine1 = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S015

S017 · implies

Before

source roles = [1, 1, [0, 1], 16, 1]

After

derived = [[0, 0], 16]

Conditions: none

Hold the other variables fixed:the coefficient becomes ck and only this coordinate exponent decreases by1.

Step identifiers and dependencies

Rule: Gradient_coordinate_power_rule_ordered_exponents · Uses: G001, S016

S018 · calculation

Before

Gradient axis1 term2 power-rule coefficient := mul(15, 1)

After

Gradient axis1 term2 power-rule coefficient = 15

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S017

S019 · calculation

Before

Gradient axis1 derivative combine2 := sum(0, 15)

After

Gradient axis1 derivative combine2 = 15

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S018

S020 · implies

Before

source roles = [1, 2, [2, 1], 15, 1]

After

derived = [[2, 0], 15]

Conditions: none

Hold the other variables fixed:the coefficient becomes ck and only this coordinate exponent decreases by1.

Step identifiers and dependencies

Rule: Gradient_coordinate_power_rule_ordered_exponents · Uses: G001, S019

S021 · implies

Before

source roles = [2, [[1, [0, 0]], [16, [0, 1]], [15, [2, 1]]]]

After

derived = [[[[30, [1, 1]]], [[16, [0, 0]], [15, [2, 0]]]]]

Conditions: none

The gradient contains all d ordered component polynomials.Polynomial differentiability makes this Euclidean vector represent the differential,not a sampled single direction.

Step identifiers and dependencies

Rule: Gradient_ALL_ordered_coordinate_polynomials · Uses: G001, S020

S022 · implies

Before

(15)^1

After

Gradient axis0 term0 coordinate0 power = 15

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S021

S023 · calculation

Before

Gradient axis0 term0 coordinate0 factor := mul(30, 15)

After

Gradient axis0 term0 coordinate0 factor = 450

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S022

S024 · implies

Before

(8)^1

After

Gradient axis0 term0 coordinate1 power = 8

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S023

S025 · calculation

Before

Gradient axis0 term0 coordinate1 factor := mul(450, 8)

After

Gradient axis0 term0 coordinate1 factor = 3600

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S024

S026 · calculation

Before

Gradient axis0 cumulative term0 := sum(0, 3600)

After

Gradient axis0 cumulative term0 = 3600

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S025

S027 · implies

Before

(15)^0

After

Gradient axis1 term0 coordinate0 power = 1

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S026

S028 · calculation

Before

Gradient axis1 term0 coordinate0 factor := mul(16, 1)

After

Gradient axis1 term0 coordinate0 factor = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S027

S029 · implies

Before

(8)^0

After

Gradient axis1 term0 coordinate1 power = 1

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S028

S030 · calculation

Before

Gradient axis1 term0 coordinate1 factor := mul(16, 1)

After

Gradient axis1 term0 coordinate1 factor = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S029

S031 · implies

Before

(15)^2

After

Gradient axis1 term1 coordinate0 power = 225

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S030

S032 · calculation

Before

Gradient axis1 term1 coordinate0 factor := mul(15, 225)

After

Gradient axis1 term1 coordinate0 factor = 3375

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S031

S033 · implies

Before

(8)^0

After

Gradient axis1 term1 coordinate1 power = 1

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S032

S034 · calculation

Before

Gradient axis1 term1 coordinate1 factor := mul(3375, 1)

After

Gradient axis1 term1 coordinate1 factor = 3375

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S033

S035 · calculation

Before

Gradient axis1 cumulative term0 := sum(0, 16)

After

Gradient axis1 cumulative term0 = 16

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S034

S036 · calculation

Before

Gradient axis1 cumulative term1 := sum(16, 3375)

After

Gradient axis1 cumulative term1 = 3391

Conditions: none

Substitute original roles and established intermediates exactly;check nonzero denominators and do not round.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S035

S037 · implies

Before

source roles = [2, [15, 8], [[[30, [1, 1]]], [[16, [0, 0]], [15, [2, 0]]]]]

After

derived = [[3600, 3391], No, No]

Conditions: none

Evaluate every component at the same point before deciding stationarity.Zero gradient supplies no automatic extremum certificate;No does not deny actual extrema of special cases such as constant functions.

Step identifiers and dependencies

Rule: Gradient_SAME_point_all_coordinates_stationary_not_extremum · Uses: G001, S036

Reverse checks

  • S037 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S036 · premise_and_result_audit — Recompute Gradient axis1 cumulative term1 with exact rational arithmetic, not rounded decimals.
  • S035 · premise_and_result_audit — Recompute Gradient axis1 cumulative term0 with exact rational arithmetic, not rounded decimals.
  • S034 · premise_and_result_audit — Recompute Gradient axis1 term1 coordinate1 factor with exact rational arithmetic, not rounded decimals.
  • S033 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S032 · premise_and_result_audit — Recompute Gradient axis1 term1 coordinate0 factor with exact rational arithmetic, not rounded decimals.
  • S031 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S030 · premise_and_result_audit — Recompute Gradient axis1 term0 coordinate1 factor with exact rational arithmetic, not rounded decimals.
  • S029 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S028 · premise_and_result_audit — Recompute Gradient axis1 term0 coordinate0 factor with exact rational arithmetic, not rounded decimals.
  • S027 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S026 · premise_and_result_audit — Recompute Gradient axis0 cumulative term0 with exact rational arithmetic, not rounded decimals.
  • S025 · premise_and_result_audit — Recompute Gradient axis0 term0 coordinate1 factor with exact rational arithmetic, not rounded decimals.
  • S024 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S023 · premise_and_result_audit — Recompute Gradient axis0 term0 coordinate0 factor with exact rational arithmetic, not rounded decimals.
  • S022 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S021 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S020 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S019 · premise_and_result_audit — Recompute Gradient axis1 derivative combine2 with exact rational arithmetic, not rounded decimals.
  • S018 · premise_and_result_audit — Recompute Gradient axis1 term2 power-rule coefficient with exact rational arithmetic, not rounded decimals.
  • S017 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S016 · premise_and_result_audit — Recompute Gradient axis1 derivative combine1 with exact rational arithmetic, not rounded decimals.
  • S015 · premise_and_result_audit — Recompute Gradient axis1 term1 power-rule coefficient with exact rational arithmetic, not rounded decimals.
  • S014 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S013 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S012 · premise_and_result_audit — Recompute Gradient axis0 derivative combine2 with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Recompute Gradient axis0 term2 power-rule coefficient with exact rational arithmetic, not rounded decimals.
  • S010 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S009 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S008 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S007 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S006 · premise_and_result_audit — Recompute Gradient ORIGINAL monomial coefficient sum2 with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S004 · premise_and_result_audit — Recompute Gradient ORIGINAL monomial coefficient sum1 with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S002 · premise_and_result_audit — Recompute Gradient ORIGINAL monomial coefficient sum0 with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(2, [[1, [0, 0]], [16, [0, 1]], [15, [2, 1]]], [15, 8], [[[30, [1, 1]]], [[16, [0, 0]], [15, [2, 0]]]], [3600, 3391], exact_rational_coordinate_evaluation)

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: 4e7284c1a14ec6642c95488f0fa340855e2b368a25f3f5b79cc58b7791e589da
  • candidate record SHA-256: 86ed8a9bbbef09d0bb3e6bb3e0355dde645c3c11f0f41fa2f6f2fb8bdcf97b36
  • semantic review receipt SHA-256: 9b43b9823e9bd2478d6caa5b57ffed161c2c8956af86974e901d5662ad994386
  • question-first witness SHA-256: eb97596068e2d5648033bab2b8f6ca9b653bbe8cb77c0f8e1d16d0c40e46f50b
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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