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Question 32324: Punctured Limit of a Removable Quotient

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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R0063-32324 · q-20261007-advance-20261008-r02-function-limit-0049

Original question and givens

On R∖{11}, f(x)=(x²−(11)²)/(x−(11)). Find its punctured two-sided limit as x→11.

  • G001 — On R∖{11}, f(x)=(x²−(11)²)/(x−(11)). Find its punctured two-sided limit as x→11.

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-function-limit-removable-quotient, removable_quotient_limit, punctured_reals, []]

After

derived = [[integer_approach_value_STRING_OMIT1]]

Conditions: none

BASE sources do not acquire a generic legacy operation/domain or unknown-metadata ban.Retain metadata WITHOUT using it as an answer oracle.PULSE/legacy enforce their exact source keys,operation/domain.Do not impose universal tuples,/1 or input bounds.

Step identifiers and dependencies

Rule: R63_SOURCE_bank_keys_operation_domain_output_roles_metadata_not_oracle · Uses: G001

S002 · calculation

Before

Removable ORIGINAL a squared := mul(11, 11)

After

Removable ORIGINAL a squared = 121

Conditions: none

Use ORIGINAL operands and order for exact integer/rational arithmetic.Raw bounds are bank-specific;derived values do not inherit SAFE or foreign small caps.No floating approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · calculation

Before

Removable ORIGINAL negative a squared constant := sub(0, 121)

After

Removable ORIGINAL negative a squared constant = -121

Conditions: none

Use ORIGINAL operands and order for exact integer/rational arithmetic.Raw bounds are bank-specific;derived values do not inherit SAFE or foreign small caps.No floating approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

Removable ORIGINAL cross terms a minus a := sub(11, 11)

After

Removable ORIGINAL cross terms a minus a = 0

Conditions: none

Use ORIGINAL operands and order for exact integer/rational arithmetic.Raw bounds are bank-specific;derived values do not inherit SAFE or foreign small caps.No floating approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

Removable ORIGINAL approach a plus a := sum(11, 11)

After

Removable ORIGINAL approach a plus a = 22

Conditions: none

Use ORIGINAL operands and order for exact integer/rational arithmetic.Raw bounds are bank-specific;derived values do not inherit SAFE or foreign small caps.No floating approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · implies

Before

source roles = [11]

After

derived = [-121, 0, 1, (x-a)*(x+a) = x^2-a^2, x-a != 0]

Conditions: none

Verify the COMPLETE coefficient identity(x−a)(x+a)=x²−a².ONLY x≠a in the punctured domain gives a nonzero denominator and permits cancellation to x+a.Never substitute0/0 at a or fill the original hole.

Step identifiers and dependencies

Rule: Limit_REMOVABLE_polynomial_factor_identity_CANCEL_ONLY_x_not_a · Uses: G001, S005

S007 · implies

Before

source roles = [11, 22]

After

derived = [(x+a)-2a = x-a, delta = epsilon, 22]

Conditions: none

With L=2a,the error is exactly|x−a|.For ANY ε>0 choose δ=ε;EVERY0<|x−a|<δ gives error<ε.This proves the punctured limit while the original quotient remains undefined at a.

Step identifiers and dependencies

Rule: Limit_REMOVABLE_punctured_error_delta_epsilon_NO_extension · Uses: G001, S006

Reverse checks

  • S007 · premise_and_result_audit — Reverse-check ORIGINAL inputs,types,domain and premises;the conclusion need not uniquely recover its premises.Keep source-bound candidates,independent review,formal proof and publication separate.
  • S006 · premise_and_result_audit — Reverse-check ORIGINAL inputs,types,domain and premises;the conclusion need not uniquely recover its premises.Keep source-bound candidates,independent review,formal proof and publication separate.
  • S005 · premise_and_result_audit — Recompute Removable ORIGINAL approach a plus a with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute Removable ORIGINAL cross terms a minus a with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute Removable ORIGINAL negative a squared constant with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute Removable ORIGINAL a squared with exact rational arithmetic, not rounded decimals.
  • S001 · premise_and_result_audit — Reverse-check ORIGINAL inputs,types,domain and premises;the conclusion need not uniquely recover its premises.Keep source-bound candidates,independent review,formal proof and publication separate.

Result

22

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: ee5c1badec0cc5e4f977bf0990fbfbceb85eb12bec003bb1c5b731c6202cd7e3
  • candidate record SHA-256: 14b828af91d1329608cb06277d1f094d4fb2a2227b44510976cbf11dc8af8d88
  • semantic review receipt SHA-256: acf03b776f4855e3869810bcbecf1116e3a2b11dfb1e2a5dfbcf8135ad24a7d0
  • question-first witness SHA-256: eadbbac3220988b52754f32450fb536d627217306d1ce28a49134f56c21bfa88
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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