Explore related knowledge and questions →

Question 1725: Normalize a Candidate before a Fixed-Factor Closed-Form Audit

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 9

← Question derivation index · Original question batch

R0002-01725 · q-20261013-advance-20261020-r06-discrete-exponential-growth-0075

Original question and givens

Use fixed discrete time steps and one exact nonnegative rational factor throughout. This is not a continuous-time model or an empirical population prediction; signed initial quantities and the zero case must retain their specified values. 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. initial=16/5, factor=1/2, n=4, candidate=2/5. Give (initial, factor, n, exact term, normalized candidate, equal?).

  • G001 — Use fixed discrete time steps and one exact nonnegative rational factor throughout. This is not a continuous-time model or an empirical population prediction; signed initial quantities and the zero case must retain their specified values. 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. initial=16/5, factor=1/2, n=4, candidate=2/5. Give (initial, factor, n, exact term, normalized candidate, 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

factor q=1/2≥0

After

X_(k+1)=q·X_k

Conditions: none

Use the same factor in the declared discrete model,rather than infer a general law from a few values.

Step identifiers and dependencies

Rule: fixed_factor_recurrence · Uses: G001

S002 · implies

Before

X₀=16/5; n=4

After

n=0 uses the initial value; an empty product equals1

Conditions: none

n counts updates;n=0 performs none.No division by q is required,so q=0 remains admissible.

Step identifiers and dependencies

Rule: initial_and_empty_product · Uses: G001, S001

S003 · calculation

Before

X_1 := mul(16/5, 1/2)

After

X_1 = 8/5

Conditions: none

Apply the same recurrence stepwise and retain each intermediate value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

X_2 := mul(8/5, 1/2)

After

X_2 = 4/5

Conditions: none

Apply the same recurrence stepwise and retain each intermediate value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

X_3 := mul(4/5, 1/2)

After

X_3 = 2/5

Conditions: none

Apply the same recurrence stepwise and retain each intermediate value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

X_4 := mul(2/5, 1/2)

After

X_4 = 1/5

Conditions: none

Apply the same recurrence stepwise and retain each intermediate value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

X_k=X₀q^k ⇒ X_(k+1)=qX_k=X₀q^(k+1)

After

X_n=X₀q^n for every nonnegative integer n

Conditions: none

The initial case holds and multiplication by q gives the induction step;this is not a guess from a finite table.

Step identifiers and dependencies

Rule: recurrence_induction · Uses: G001, S006

S008 · implies

Before

(1/2)^4

After

q^n = 1/16

Conditions: none

Evaluate the finite nonnegative-integer power exactly; exponent0 uses the polynomial multiplicative identity.

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S007

S009 · calculation

Before

closed-form X_n := mul(16/5, 1/16)

After

closed-form X_n = 1/5

Conditions: none

Substitute into the power formula as a separate calculation;it must equal the stepwise update.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

computed X_4=1/5; candidate=2/5

After

candidate correct at this n: No

Conditions: none

Check the candidate value at this index;one agreement would not prove an arbitrary candidate formula globally.

Step identifiers and dependencies

Rule: candidate_at_index · Uses: G001, S009

Reverse checks

  • 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 closed-form X_n 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S006 · premise_and_result_audit — Recompute X_4 with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute X_3 with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute X_2 with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute X_1 with exact rational arithmetic, not rounded decimals.
  • 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

(16/5, 1/2, 4, 1/5, 2/5, 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: 51a905b6566df0605e650af95cd9aa5ee72b34a1cef4897592f5ffb4164f0c69
  • candidate record SHA-256: b0b75672b06ee3e038b159d550d698628f68d6e23510e9b5c764437e74cad091
  • semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
  • question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON