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Question 10344: Conjugating a Product versus Multiplying the Conjugates

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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R0019-10344 · q-20261013-advance-20261023-r01-complex-modulus-conjugate-0094

Original question and givens

Use integer ordered pairs [a,b] for a+b*i, with i²=−1. Conjugation reverses the imaginary coefficient, not the real part. Modulus squared is a²+b²; do not replace it with a square root or a decimal approximation. No complex-analysis conclusion is claimed. left=[6, 1], right=[1, 27]. Give (left,right,product,conjugate of product,product of conjugates,equal?).

  • G001 — Use integer ordered pairs [a,b] for a+b*i, with i²=−1. Conjugation reverses the imaginary coefficient, not the real part. Modulus squared is a²+b²; do not replace it with a square root or a decimal approximation. No complex-analysis conclusion is claimed. left=[6, 1], right=[1, 27]. Give (left,right,product,conjugate of product,product of conjugates,equal?).

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

declared complex ordered pair=[6, 1]

After

exact integer coefficients in the algebra with i^2=-1

Conditions: none

Use the declared complex algebra,not componentwise real-vector multiplication.The zero complex number is allowed.

Step identifiers and dependencies

Rule: exact_complex_pair_scope · Uses: G001

S002 · calculation

Before

original product real-real := mul(6, 1)

After

original product real-real = 6

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, S001

S003 · calculation

Before

original product imaginary-imaginary := mul(1, 27)

After

original product imaginary-imaginary = 27

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, S002

S004 · calculation

Before

original product real coefficient := sub(6, 27)

After

original product real coefficient = -21

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

original product real-imaginary := mul(6, 27)

After

original product real-imaginary = 162

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 · calculation

Before

original product imaginary-real := mul(1, 1)

After

original product imaginary-real = 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, S005

S007 · calculation

Before

original product imaginary coefficient := sum(162, 1)

After

original product imaginary coefficient = 163

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 · implies

Before

original product:left=[6, 1];right=[1, 27];i^2=-1

After

complex product=[-21, 163]

Conditions: none

Expand(a+bi)(c+di)=(ac−bd)+(ad+bc)i,retaining each of the four products' source positions and signs.

Step identifiers and dependencies

Rule: complex_product_ordered_component_expansion · Uses: G001, S007

S009 · calculation

Before

original product negate imaginary coefficient := sub(0, 163)

After

original product negate imaginary coefficient = -163

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

original product:original ordered pair=[-21, 163]

After

conjugate pair=[-21, -163]

Conditions: none

The pair(a,b) denotes a+bi.Conjugation fixes the real part and negates only b;it does not exchange coordinates.

Step identifiers and dependencies

Rule: complex_conjugate_real_fixed_imaginary_negated · Uses: G001, S009

S011 · calculation

Before

left value negate imaginary coefficient := sub(0, 1)

After

left value negate imaginary coefficient = -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 · implies

Before

left value:original ordered pair=[6, 1]

After

conjugate pair=[6, -1]

Conditions: none

The pair(a,b) denotes a+bi.Conjugation fixes the real part and negates only b;it does not exchange coordinates.

Step identifiers and dependencies

Rule: complex_conjugate_real_fixed_imaginary_negated · Uses: G001, S011

S013 · calculation

Before

right value negate imaginary coefficient := sub(0, 27)

After

right value negate imaginary coefficient = -27

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, S012

S014 · implies

Before

right value:original ordered pair=[1, 27]

After

conjugate pair=[1, -27]

Conditions: none

The pair(a,b) denotes a+bi.Conjugation fixes the real part and negates only b;it does not exchange coordinates.

Step identifiers and dependencies

Rule: complex_conjugate_real_fixed_imaginary_negated · Uses: G001, S013

S015 · calculation

Before

product of conjugates real-real := mul(6, 1)

After

product of conjugates real-real = 6

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, S014

S016 · calculation

Before

product of conjugates imaginary-imaginary := mul(-1, -27)

After

product of conjugates imaginary-imaginary = 27

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, S015

S017 · calculation

Before

product of conjugates real coefficient := sub(6, 27)

After

product of conjugates real coefficient = -21

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, S016

S018 · calculation

Before

product of conjugates real-imaginary := mul(6, -27)

After

product of conjugates real-imaginary = -162

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, S017

S019 · calculation

Before

product of conjugates imaginary-real := mul(-1, 1)

After

product of conjugates imaginary-real = -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, S018

S020 · calculation

Before

product of conjugates imaginary coefficient := sum(-162, -1)

After

product of conjugates imaginary coefficient = -163

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, S019

S021 · implies

Before

product of conjugates:left=[6, -1];right=[1, -27];i^2=-1

After

complex product=[-21, -163]

Conditions: none

Expand(a+bi)(c+di)=(ac−bd)+(ad+bc)i,retaining each of the four products' source positions and signs.

Step identifiers and dependencies

Rule: complex_product_ordered_component_expansion · Uses: G001, S020

S022 · implies

Before

conjugate of computed product=[-21, -163];computed product of conjugates=[-21, -163]

After

equal=Yes

Conditions: none

Expand both routes completely,retaining original left/right roles and every intermediate pair.These exact instances are not new general formal Evidence.

Step identifiers and dependencies

Rule: conjugation_product_two_routes · Uses: G001, S021

Reverse checks

  • 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 — Recompute product of conjugates imaginary coefficient with exact rational arithmetic, not rounded decimals.
  • S019 · premise_and_result_audit — Recompute product of conjugates imaginary-real with exact rational arithmetic, not rounded decimals.
  • S018 · premise_and_result_audit — Recompute product of conjugates real-imaginary with exact rational arithmetic, not rounded decimals.
  • S017 · premise_and_result_audit — Recompute product of conjugates real coefficient with exact rational arithmetic, not rounded decimals.
  • S016 · premise_and_result_audit — Recompute product of conjugates imaginary-imaginary with exact rational arithmetic, not rounded decimals.
  • S015 · premise_and_result_audit — Recompute product of conjugates real-real 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 — Recompute right value negate imaginary coefficient with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S011 · premise_and_result_audit — Recompute left value negate imaginary 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 — Recompute original product negate imaginary coefficient with exact rational arithmetic, not rounded decimals.
  • 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 — Recompute original product imaginary coefficient with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute original product imaginary-real with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute original product real-imaginary with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute original product real coefficient with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute original product imaginary-imaginary with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute original product real-real 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

([6, 1], [1, 27], [-21, 163], [-21, -163], [-21, -163], 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: 7375d4e8601a32b0c867c5dd6b098489e31450e8c36177d50135ed043beecae4
  • candidate record SHA-256: a6eac548b0a421a2d94f2399f2a7f8da8d3c1b9611f1b9a3a94e294547e80037
  • semantic review receipt SHA-256: eeb35dc5daab92234bf72827627392b47f38ead4cfb574d4373bebc43c09fbf5
  • question-first witness SHA-256: 3cf8e0d3a00b0df1994db2bfde81f4a31b382e170bdda83ea3d0b68da64e8419
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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