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Question 10013: Verifying a Difference-of-Squares Identity

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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R0019-10013 · q-20261003-r03-factorization-0088

Original question and givens

In Q[x], coefficient vectors are ordered from lowest to highest power. Is the difference of squares x²−(12)² equal to the proposed coefficient vector [-144, 0, 1]? Answer Yes or No.

  • G001 — In Q[x], coefficient vectors are ordered from lowest to highest power. Is the difference of squares x²−(12)² equal to the proposed coefficient vector [-144, 0, 1]? Answer Yes or No.

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

Q[x];ascending coefficients;input vectors may have trailing zeros

After

equality uses every normalized coefficient,not numerical sampling

Conditions: none

Preserve the original factor order and vectors.Normalization removes only trailing high-power zeros;do not reorder source factors by semantic identity or infer polynomial equality from one point.

Step identifiers and dependencies

Rule: factorization_coefficient_identity_scope · Uses: G001

S002 · implies

Before

original d=12;x^2-d^2

After

factors x-d and x+d;ascending vectors=[[-12, 1], [12, 1]]

Conditions: none

Expand(x−d)(x+d)=x²+dx−dx−d²,retaining the original sign of d.The same expansion applies for negative d or d=0.

Step identifiers and dependencies

Rule: difference_of_squares_actual_signed_parameter · Uses: G001, S001

S003 · implies

Before

power k=0;left=[-12, 1];right=[12, 1]

After

all index pairs i+j=k=[[0, 0]]

Conditions: none

Ascending-vector indices are powers.Collect every valid pair with i+j=k;polynomial multiplication is not entrywise multiplication.

Step identifiers and dependencies

Rule: product_coefficient_complete_index_pairs · Uses: G001, S002

S004 · calculation

Before

coefficient0 term0,0 := mul(-12, 12)

After

coefficient0 term0,0 = -144

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

coefficient0 complete sum := sum(-144)

After

coefficient0 complete sum = -144

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · implies

Before

power k=1;left=[-12, 1];right=[12, 1]

After

all index pairs i+j=k=[[0, 1], [1, 0]]

Conditions: none

Ascending-vector indices are powers.Collect every valid pair with i+j=k;polynomial multiplication is not entrywise multiplication.

Step identifiers and dependencies

Rule: product_coefficient_complete_index_pairs · Uses: G001, S005

S007 · calculation

Before

coefficient1 term0,1 := mul(-12, 1)

After

coefficient1 term0,1 = -12

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · calculation

Before

coefficient1 term1,0 := mul(1, 12)

After

coefficient1 term1,0 = 12

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · calculation

Before

coefficient1 complete sum := sum(-12, 12)

After

coefficient1 complete sum = 0

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

power k=2;left=[-12, 1];right=[12, 1]

After

all index pairs i+j=k=[[1, 1]]

Conditions: none

Ascending-vector indices are powers.Collect every valid pair with i+j=k;polynomial multiplication is not entrywise multiplication.

Step identifiers and dependencies

Rule: product_coefficient_complete_index_pairs · Uses: G001, S009

S011 · calculation

Before

coefficient2 term1,1 := mul(1, 1)

After

coefficient2 term1,1 = 1

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S010

S012 · calculation

Before

coefficient2 complete sum := sum(1)

After

coefficient2 complete sum = 1

Conditions: none

Compute exactly from this step's original operands in the specified order,retaining signs and denominator conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · implies

Before

all collected product coefficients=[-144, 0, 1]

After

normalized complete product=[-144, 0, 1]

Conditions: none

All finitely many coefficients were obtained.Remove trailing high-power zeros and display zero as[0].This is coefficient identity,not agreement at a few sample points.

Step identifiers and dependencies

Rule: complete_product_not_sampled_values · Uses: G001, S012

S014 · implies

Before

power k=0;actual coefficient=-144;candidate coefficient=-144

After

coefficient matches=Yes

Conditions: none

Treat absent higher coefficients as0 and compare through the larger degree.The supplied candidate is not overwritten by the correct product.

Step identifiers and dependencies

Rule: every_identity_coefficient_comparison · Uses: G001, S013

S015 · implies

Before

power k=1;actual coefficient=0;candidate coefficient=0

After

coefficient matches=Yes

Conditions: none

Treat absent higher coefficients as0 and compare through the larger degree.The supplied candidate is not overwritten by the correct product.

Step identifiers and dependencies

Rule: every_identity_coefficient_comparison · Uses: G001, S014

S016 · implies

Before

power k=2;actual coefficient=1;candidate coefficient=1

After

coefficient matches=Yes

Conditions: none

Treat absent higher coefficients as0 and compare through the larger degree.The supplied candidate is not overwritten by the correct product.

Step identifiers and dependencies

Rule: every_identity_coefficient_comparison · Uses: G001, S015

S017 · implies

Before

raw proposed=[-144, 0, 1];normalized proposed=[-144, 0, 1];actual product=[-144, 0, 1]

After

coefficient identity=Yes

Conditions: none

Identity requires equality of all coefficients,including the both-zero case.Constants and trailing-zero representations do not create a different polynomial.

Step identifiers and dependencies

Rule: factorization_final_full_identity_gate · Uses: G001, S016

Reverse checks

  • 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S015 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 coefficient2 complete sum with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Recompute coefficient2 term1,1 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 — Recompute coefficient1 complete sum with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Recompute coefficient1 term1,0 with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute coefficient1 term0,1 with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S005 · premise_and_result_audit — Recompute coefficient0 complete sum with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute coefficient0 term0,0 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

Yes

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: c45c3cc201d4a11fe33aa2d169d04137fef3a156f9d7385c247984ebeb4dceb6
  • candidate record SHA-256: cdfac856b2ba950d28fdb5cda1b3de22e8eefa3ba5052adfbbed9bc84f8d38f0
  • semantic review receipt SHA-256: eeb35dc5daab92234bf72827627392b47f38ead4cfb574d4373bebc43c09fbf5
  • question-first witness SHA-256: 3cf8e0d3a00b0df1994db2bfde81f4a31b382e170bdda83ea3d0b68da64e8419
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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