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Question 1674: Relative Error with an Explicit Nonzero Reference

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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R0002-01674 · q-20261013-advance-20261020-r03-numerical-approximation-error-0049

Original question and givens

Use exact rational inputs. Normalize denominator signs and reduce output fractions; print integers without /1. These specified-value checks do not identify truncation, rounding, measurement or model-error causes. approximation=49/4, reference=6/4 is required to be nonzero. Give (approximation, reference, absolute error, absolute error divided by absolute reference). Do not convert the ratio to a percentage.

  • G001 — Use exact rational inputs. Normalize denominator signs and reduce output fractions; print integers without /1. These specified-value checks do not identify truncation, rounding, measurement or model-error causes. approximation=49/4, reference=6/4 is required to be nonzero. Give (approximation, reference, absolute error, absolute error divided by absolute reference). Do not convert the ratio to a percentage.

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

reference=3/2

After

all values are exact rationals

Conditions: none

This is exact error arithmetic against a specified reference,without floating-point rounding that could alter an equality boundary.

Step identifiers and dependencies

Rule: exact_error_model · Uses: G001

S002 · calculation

Before

approximation−reference := sub(49/4, 3/2)

After

approximation−reference = 43/4

Conditions: none

Compute the signed error as approximation minus reference.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

absolute error := mul(1, 43/4)

After

absolute error = 43/4

Conditions: none

Use the sign to take the absolute value;the result is nonnegative.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

signed error=43/4

After

absolute error=43/4≥0

Conditions: none

Absolute error has the original quantity's units;a negative reference does not make it negative.

Step identifiers and dependencies

Rule: absolute_error_definition · Uses: G001, S003

S005 · implies

Before

reference=3/2≠0

After

relative denominator=|reference|=3/2>0

Conditions: none

Divide by the absolute reference;this definition does not apply at reference0.

Step identifiers and dependencies

Rule: relative_denominator_guard · Uses: G001, S004

S006 · calculation

Before

relative error := div(43/4, 3/2)

After

relative error = 43/6

Conditions: none

Divide by the positive denominator for a dimensionless ratio,without multiplying by100.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

relative error=43/6

After

ratio may exceed1; it is not a probability

Conditions: none

Relative error may exceed1;only a separate percent conversion multiplies by100,so ratio2 is not2%.

Step identifiers and dependencies

Rule: relative_error_scope · Uses: G001, S006

Reverse checks

  • 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 relative error 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Recompute absolute error with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute approximation−reference 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

(49/4, 3/2, 43/4, 43/6)

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: 0667128baff21406b60783af2d69dc995dbd3fa4931c5d7bc3eec7ae126d3a38
  • candidate record SHA-256: 42ecb5d379d8d9b58537c6ed12b1bccd82362406918270aa047d53cc78d98b00
  • semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
  • question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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