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Question 33571: A Fixed-x Slice and Its y-Derivative

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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R0066-33571 · q-20261013-advance-20261025-r07-partial-derivative-0071

Original question and givens

Use the quadratic candidate coefficients=[8, -2, 3, 1, 1, -2] in fixed order [1,x,y,x²,x*y,y²]. Fix the other coordinate before taking a one-variable derivative. These symbolic polynomial identities do not replace a limit by one finite-difference sample or establish total differentiability of general functions. fixed x=-2, evaluation y=3. Give (coefficients,fixed x,ascending y-slice coefficients,ascending derivative coefficients,y,derivative value).

  • G001 — Use the quadratic candidate coefficients=[8, -2, 3, 1, 1, -2] in fixed order [1,x,y,x²,x*y,y²]. Fix the other coordinate before taking a one-variable derivative. These symbolic polynomial identities do not replace a limit by one finite-difference sample or establish total differentiability of general functions. fixed x=-2, evaluation y=3. Give (coefficients,fixed x,ascending y-slice coefficients,ascending derivative coefficients,y,derivative value).

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 = [qf-mod25-partialdeep-partial-y-slice-derivative, [coefficients, domain, fixed_x, operation, y]]

After

derived = [partialdeep-partial-y-slice-derivative, Polynomial_partial_derivative_density]

Conditions: none

THIS source uses LOCAL-hyphen operations with exact keys/domain.Keep source field order and numeric/Boolean/string roles;integer rational texts omit/1.Original questions,English,MKOs,ASTs and statuses remain unchanged.

Step identifiers and dependencies

Rule: R66_EXACT_source_bank_keys_local_operation_domain · Uses: G001

S002 · implies

Before

source roles = [[8, -2, 3, 1, 1, -2]]

After

derived = [1, x, y, x^2, x*y, y^2]

Conditions: none

The SIX coefficients use the full[1,x,y,x²,xy,y²]basis.Hold the OTHER coordinate fixed.This supplied polynomial supports symbolic identities,not inference of a derivative from one difference sample or total differentiability of arbitrary functions.

Step identifiers and dependencies

Rule: Partial_FULL_polynomial_basis_and_fixed_other_coordinate · Uses: G001, S001

S003 · calculation

Before

Slice ORIGINAL c_x times fixed x := mul(-2, -2)

After

Slice ORIGINAL c_x times fixed x = 4

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

Slice ORIGINAL fixed x squared := mul(-2, -2)

After

Slice ORIGINAL fixed x squared = 4

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

Slice ORIGINAL c_xx times fixed x squared := mul(1, 4)

After

Slice ORIGINAL c_xx times fixed x squared = 4

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

Slice ORIGINAL constant terms sum := sum(8, 4, 4)

After

Slice ORIGINAL constant terms sum = 16

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

Slice ORIGINAL c_xy times fixed x := mul(1, -2)

After

Slice ORIGINAL c_xy times fixed x = -2

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · calculation

Before

Slice ORIGINAL linear y terms sum := sum(3, -2)

After

Slice ORIGINAL linear y terms sum = 1

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · calculation

Before

Slice ORIGINAL twice c_yy := mul(2, -2)

After

Slice ORIGINAL twice c_yy = -4

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

source roles = [[8, -2, 3, 1, 1, -2], -2]

After

derived = [[16, 1, -2], [1, -4]]

Conditions: none

FIRST fix x and collect the WHOLE y-polynomial s0+s1*y+s2*y².THEN differentiate to s1+2*s2*y.Do not substitute BOTH coordinates into a constant before differentiating.

Step identifiers and dependencies

Rule: Partial_FIXED_x_whole_y_polynomial_THEN_derivative · Uses: G001, S009

S011 · calculation

Before

Slice ORIGINAL derivative linear term at y := mul(-4, 3)

After

Slice ORIGINAL derivative linear term at y = -12

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S010

S012 · calculation

Before

Slice ORIGINAL full derivative value := sum(1, -12)

After

Slice ORIGINAL full derivative value = -11

Conditions: none

Calculate exactly from THIS step’s ORIGINAL ordered operands.Retain the SOURCE rational pre-reduction envelope separately;do not use floating values or silently widen a different bank.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

Reverse checks

  • S012 · premise_and_result_audit — Recompute Slice ORIGINAL full derivative value with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Recompute Slice ORIGINAL derivative linear term at y with exact rational arithmetic, not rounded decimals.
  • S010 · premise_and_result_audit — Reverse-audit THIS step against its ORIGINAL ordered roles and complete premises.Accept the conclusion only under these conditions;do not invert a one-way implication or call a finite check a general formal proof.
  • S009 · premise_and_result_audit — Recompute Slice ORIGINAL twice c_yy with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Recompute Slice ORIGINAL linear y terms sum with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute Slice ORIGINAL c_xy times fixed x with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute Slice ORIGINAL constant terms sum with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute Slice ORIGINAL c_xx times fixed x squared with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute Slice ORIGINAL fixed x squared with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute Slice ORIGINAL c_x times fixed x with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Reverse-audit THIS step against its ORIGINAL ordered roles and complete premises.Accept the conclusion only under these conditions;do not invert a one-way implication or call a finite check a general formal proof.
  • S001 · premise_and_result_audit — Reverse-audit THIS step against its ORIGINAL ordered roles and complete premises.Accept the conclusion only under these conditions;do not invert a one-way implication or call a finite check a general formal proof.

Result

([8, -2, 3, 1, 1, -2], -2, [16, 1, -2], [1, -4], 3, -11)

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: f82a263d7b4b0c32b61c112b24dfd1e4429a8f7db516efd220f9b88aad99a095
  • candidate record SHA-256: e1f2c8b5e68e6ed91c7ee823e378d9821446c6f100fbc9d282c27b0a945c44bd
  • semantic review receipt SHA-256: 99b4f114b2ec93164b6aa5681e0107033a240e7a3f0a8988633ba65320ede267
  • question-first witness SHA-256: d9bd3a1940da8a73f790ee3fe460c9a8523791bdbe72c8e0304e3740b66710cc
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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