Explore related knowledge and questions →

Question 10380: The Product with the Conjugate Is a Real Embedding

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

Return to catalogue page 52

← Question derivation index · Original question batch

R0019-10380 · q-20261013-advance-20261023-r01-complex-modulus-conjugate-0055

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. value=[-8, 1]. Give (value,conjugate,product as a complex pair,modulus squared).

  • 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. value=[-8, 1]. Give (value,conjugate,product as a complex pair,modulus squared).

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=[-8, 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

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

After

given 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, S001

S003 · implies

Before

given value:original ordered pair=[-8, 1]

After

conjugate pair=[-8, -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, S002

S004 · calculation

Before

value times conjugate real-real := mul(-8, -8)

After

value times conjugate real-real = 64

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

value times conjugate imaginary-imaginary := mul(1, -1)

After

value times conjugate imaginary-imaginary = -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, S004

S006 · calculation

Before

value times conjugate real coefficient := sub(64, -1)

After

value times conjugate real coefficient = 65

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

value times conjugate real-imaginary := mul(-8, -1)

After

value times conjugate real-imaginary = 8

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

value times conjugate imaginary-real := mul(1, -8)

After

value times conjugate imaginary-real = -8

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

value times conjugate imaginary coefficient := sum(8, -8)

After

value times conjugate imaginary coefficient = 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

value times conjugate:left=[-8, 1];right=[-8, -1];i^2=-1

After

complex product=[65, 0]

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, S009

S011 · calculation

Before

real coefficient squared := mul(-8, -8)

After

real coefficient squared = 64

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

imaginary coefficient squared := mul(1, 1)

After

imaginary coefficient squared = 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 · calculation

Before

exact squared modulus := sum(64, 1)

After

exact squared modulus = 65

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

value=[-8, 1];real square=64;imaginary square=1

After

modulus squared=65

Conditions: none

The requested value is|z|²=a²+b²,not|z|.Do not substitute a radical,approximation or negative square root.

Step identifiers and dependencies

Rule: modulus_squared_not_unrequested_square_root · Uses: G001, S013

S015 · implies

Before

computed product=[65, 0];squared modulus=65

After

product is real embedding [modulus squared,0]

Conditions: none

The computed imaginary coefficient cancels to0,and the real coefficient equals the sum of squares.The product was not merely filled from an expected answer.

Step identifiers and dependencies

Rule: complex_times_conjugate_imaginary_cancellation · Uses: G001, S014

Reverse checks

  • 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 — Recompute exact squared modulus with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Recompute imaginary coefficient squared with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Recompute real coefficient squared 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 value times conjugate imaginary coefficient with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Recompute value times conjugate imaginary-real with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute value times conjugate real-imaginary with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute value times conjugate real coefficient with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute value times conjugate imaginary-imaginary with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute value times conjugate real-real 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 given value negate imaginary coefficient 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

([-8, 1], [-8, -1], [65, 0], 65)

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: a1d991be0008ea80efbe4593f45c62acfd71c362dd5f70d7796dfc929d556f58
  • candidate record SHA-256: d19eb81ddeedd9ff555b1977570fc275d5b82d2b9d110afefb3df5cc8c5fdab6
  • semantic review receipt SHA-256: eeb35dc5daab92234bf72827627392b47f38ead4cfb574d4373bebc43c09fbf5
  • question-first witness SHA-256: 3cf8e0d3a00b0df1994db2bfde81f4a31b382e170bdda83ea3d0b68da64e8419
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON