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Question 1632: Inclusive Error Interval and a Candidate Boundary

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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R0002-01632 · q-20261013-advance-20261020-r03-numerical-approximation-error-0082

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. reference=7/3, tolerance=1/8≥0, candidate=13/2. Give (reference, tolerance, reference−tolerance, reference+tolerance, candidate, inside the inclusive interval?).

  • 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. reference=7/3, tolerance=1/8≥0, candidate=13/2. Give (reference, tolerance, reference−tolerance, reference+tolerance, candidate, inside the inclusive interval?).

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=7/3

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

reference−tolerance := sub(7/3, 1/8)

After

reference−tolerance = 53/24

Conditions: none

Compute the closed interval's lower endpoint.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

reference+tolerance := sum(7/3, 1/8)

After

reference+tolerance = 59/24

Conditions: none

Then compute its upper endpoint.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

|candidate−reference|≤tolerance

After

reference−tolerance≤candidate≤reference+tolerance

Conditions: none

Add the reference to the two-sided signed-error bound to obtain the closed interval;endpoints are included.

Step identifiers and dependencies

Rule: closed_interval_equivalence · Uses: G001, S003

S005 · calculation

Before

candidate−reference := sub(13/2, 7/3)

After

candidate−reference = 25/6

Conditions: none

Calculate the actual deviation as a reverse check on interval membership.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · implies

Before

candidate=13/2; |deviation|=25/6

After

inside closed interval: No

Conditions: none

The absolute-error and closed-interval tests agree;zero tolerance allows only the reference itself.

Step identifiers and dependencies

Rule: interval_membership · Uses: G001, S005

Reverse checks

  • 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 candidate−reference with exact rational arithmetic, not rounded decimals.
  • 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 reference+tolerance with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute reference−tolerance 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

(7/3, 1/8, 53/24, 59/24, 13/2, No)

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: 10bd19a9c082b32e9a065ee3392beeadffbc2b9e0942df14e635bc227ee76169
  • candidate record SHA-256: 32927f35d75daa8146709b2895ea78ea1668180550fb48a11ed50644266bf700
  • semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
  • question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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