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Question 35081: Term of a Zero-Based Explicit Sequence

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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R0069-35081 · q-20260930-r05-sequence-explicit-term-0006

Original question and givens

The real sequence is indexed from 0 and has the explicit rule a_n=(-7)+(2)n for n∈N={0,1,2,…}. Find the term at n=5.

  • G001 — The real sequence is indexed from 0 and has the explicit rule a_n=(-7)+(2)n for n∈N={0,1,2,…}. Find the term at n=5.

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

source roles = [qf-sequence-explicit-term, [d, n, operation, u]]

After

derived = [explicit_term, no-invented-domain]

Conditions: none

Keep EACH bank’s keys/operation/domain distinct:LDL/PULSE/function legacy table underscores,TREE full tree_* with its declared domain,and permissive BASE signed without invented op/domain.All arithmetic respects the binary-primitive contract.

Step identifiers and dependencies

Rule: R69_SOURCE_specific_keys_operation_domain_AND_binary_contract · Uses: G001

S002 · implies

Before

source roles = [-7, 2, 5, explicit_term]

After

derived = [a_0=u, a_n=u+n*d, zero based]

Conditions: none

Type ALL RAW u/d/count fields EVEN for prefix L=0.Indices start at0 and the formula/recurrence is GIVEN;do not infer a general rule from finite samples.

Step identifiers and dependencies

Rule: Sequence_ALL_RAW_initial_step_and_count_EVEN_empty_prefix · Uses: G001, S001

S003 · calculation

Before

Sequence ORIGINAL zero-based n times common difference := mul(5, 2)

After

Sequence ORIGINAL zero-based n times common difference = 10

Conditions: none

Use ORIGINAL operands exactly;mul/sub/div have EXPLICITLY TWO operands so the old binary primitive cannot ignore a third.Keep RAW SAFE bounds separate from unbounded derived BigInts;do not approximate to force answers.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

Sequence ORIGINAL initial plus n common differences := sum(-7, 10)

After

Sequence ORIGINAL initial plus n common differences = 3

Conditions: none

Use ORIGINAL operands exactly;mul/sub/div have EXPLICITLY TWO operands so the old binary primitive cannot ignore a third.Keep RAW SAFE bounds separate from unbounded derived BigInts;do not approximate to force answers.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · implies

Before

source roles = [-7, 2, 5]

After

derived = [3]

Conditions: none

Substitute THIS n into u+n*d.At n=0 recover a0=u;negative d is allowed.Derived BigInts are not recapped at RAW SAFE;one term does not prove a limit.

Step identifiers and dependencies

Rule: Sequence_EXPLICIT_complete_substitution_NO_limit_claim · Uses: G001, S004

Reverse checks

  • S005 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S004 · premise_and_result_audit — Recompute Sequence ORIGINAL initial plus n common differences with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute Sequence ORIGINAL zero-based n times common difference with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.
  • S001 · premise_and_result_audit — Reverse-audit THIS question’s ORIGINAL data,types,roles,complete premises and field order.Do not invert implication or turn finite-table checks into infinite-domain/formal proof.Original Q/English/MKO/AST/status remain unchanged.

Result

3

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: 4dc592d32043cc6a9cc3a5c4954f812e7de343dc8736ffd77f48c7626d8459cd
  • candidate record SHA-256: 59f1c9a82050ea6a1f4b34e6f5bad1ebe5ce1e7e06dac5662e06b4054b6ee30e
  • semantic review receipt SHA-256: ccf93c72638d6abf6a412514da5838d55ecb09b71d0e4fdec2b559dc9fdee14b
  • question-first witness SHA-256: 11af9a338b5a610342b2cfb2ee295683131b3139ac402dd19b1ba1725976d518
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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