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Question 1758: The Exact Natural-Indexed Term Including Zero Factor and Time

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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R0002-01758 · q-20261013-advance-20261020-r06-discrete-exponential-growth-0033

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=-1/3, factor=4/3, n=2≥0. Give (initial, factor, n, initial*factor^n). The zeroth power is the empty product 1, including factor=0.

  • 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=-1/3, factor=4/3, n=2≥0. Give (initial, factor, n, initial*factor^n). The zeroth power is the empty product 1, including factor=0.

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=4/3≥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=-1/3; n=2

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(-1/3, 4/3)

After

X_1 = -4/9

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(-4/9, 4/3)

After

X_2 = -16/27

Conditions: none

Apply the same recurrence stepwise and retain each intermediate value.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · 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, S004

S006 · implies

Before

(4/3)^2

After

q^n = 16/9

Conditions: none

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

Step identifiers and dependencies

Rule: integer_power · Uses: G001, S005

S007 · calculation

Before

closed-form X_n := mul(-1/3, 16/9)

After

closed-form X_n = -16/27

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, S006

Reverse checks

  • S007 · premise_and_result_audit — Recompute closed-form X_n with exact rational arithmetic, not rounded decimals.
  • 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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

(-1/3, 4/3, 2, -16/27)

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: 8f0e41e9a1aa19801631b49ffc4bd00787713192058bf6c236a2a178eaa15e08
  • candidate record SHA-256: a25ea052e2ddfb70b7b0651c66d71bf710923f89a9d64b8ab4a2f9dcf5026d99
  • semantic review receipt SHA-256: 340d74dcc6e37df6249594a0b79a9ee2af804337b7847478b3c1342af9722861
  • question-first witness SHA-256: 9a06233d190d31a16f13fb03b6c3ceba4cbb748fff6c997941f66ab1888dcca8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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