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Question 32336: Two-Sided Limit of Affine Branches

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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R0063-32336 · q-20261007-advance-20261008-r02-function-limit-0086

Original question and givens

On the punctured domain R∖{-2}, The left branch at x<-2 is (3)x+(4); the right branch at x>-2 is (-2)x+(7). Find the finite two-sided limit, or answer does not exist when the two side limits differ.

  • G001 — On the punctured domain R∖{-2}, The left branch at x<-2 is (3)x+(4); the right branch at x>-2 is (-2)x+(7). Find the finite two-sided limit, or answer does not exist when the two side limits differ.

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-two-sided-affine, two_sided_affine_limit, punctured_reals, []]

After

derived = [[integer_approach_value_OR_source_nonexistence_STRING]]

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

LEFT affine approach ORIGINAL slope times approach center := mul(3, -2)

After

LEFT affine approach ORIGINAL slope times approach center = -6

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

LEFT affine approach ORIGINAL approach affine constant sum := sum(-6, 4)

After

LEFT affine approach ORIGINAL approach affine constant sum = -2

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

LEFT affine approach ORIGINAL positive slope bound one plus abs m := sum(1, 3)

After

LEFT affine approach ORIGINAL positive slope bound one plus abs m = 4

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 · implies

Before

source roles = [LEFT affine approach, 3, 4, -2]

After

derived = [-2, 4, error = m*(x-a), delta = epsilon/4]

Conditions: none

For the WHOLE GIVEN affine law,f(x)−L=m(x−a).For ANY ε>0 choose δ=ε/(1+|m|)>0;on the declared side/punctured domain,0<|x−a|<δ gives error<ε.At m0 the error is0.This is an APPROACH value,not assignment of original f(a)or a sample-based proof.

Step identifiers and dependencies

Rule: Limit_AFFINE_whole_law_error_epsilon_delta_NOT_center_assignment · Uses: G001, S004

S006 · calculation

Before

RIGHT affine approach ORIGINAL slope times approach center := mul(-2, -2)

After

RIGHT affine approach ORIGINAL slope times approach center = 4

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, S005

S007 · calculation

Before

RIGHT affine approach ORIGINAL approach affine constant sum := sum(4, 7)

After

RIGHT affine approach ORIGINAL approach affine constant sum = 11

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, S006

S008 · calculation

Before

RIGHT affine approach ORIGINAL positive slope bound one plus abs m := sum(1, 2)

After

RIGHT affine approach ORIGINAL positive slope bound one plus abs m = 3

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, S007

S009 · implies

Before

source roles = [RIGHT affine approach, -2, 7, -2]

After

derived = [11, 3, error = m*(x-a), delta = epsilon/3]

Conditions: none

For the WHOLE GIVEN affine law,f(x)−L=m(x−a).For ANY ε>0 choose δ=ε/(1+|m|)>0;on the declared side/punctured domain,0<|x−a|<δ gives error<ε.At m0 the error is0.This is an APPROACH value,not assignment of original f(a)or a sample-based proof.

Step identifiers and dependencies

Rule: Limit_AFFINE_whole_law_error_epsilon_delta_NOT_center_assignment · Uses: G001, S008

S010 · calculation

Before

Two-sided ORIGINAL left minus right approach values := sub(-2, 11)

After

Two-sided ORIGINAL left minus right approach values = -13

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, S009

S011 · calculation

Before

Two-sided ORIGINAL positive separation scale gap over3 := div(13, 3)

After

Two-sided ORIGINAL positive separation scale gap over3 = 13/3

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, S010

S012 · implies

Before

source roles = [-2, -2, 11]

After

derived = [-13, 13/3, two-sided-limit: does not exist]

Conditions: none

If a two-sided limit existed,BOTH side restrictions would have that SAME limit.Real limits are unique,but the proven side values differ,so this is impossible.Positive gap/3 separates their neighborhoods.What fails is the COMMON two-sided limit,not either one-sided limit;this is not a sample-based decision.

Step identifiers and dependencies

Rule: Limit_TWO_sides_DIFFER_necessity_uniqueness_context_qualified_absence · Uses: G001, S011

Reverse checks

  • S012 · 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.
  • S011 · premise_and_result_audit — Recompute Two-sided ORIGINAL positive separation scale gap over3 with exact rational arithmetic, not rounded decimals.
  • S010 · premise_and_result_audit — Recompute Two-sided ORIGINAL left minus right approach values with exact rational arithmetic, not rounded decimals.
  • S009 · 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.
  • S008 · premise_and_result_audit — Recompute RIGHT affine approach ORIGINAL positive slope bound one plus abs m with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute RIGHT affine approach ORIGINAL approach affine constant sum with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute RIGHT affine approach ORIGINAL slope times approach center with exact rational arithmetic, not rounded decimals.
  • S005 · 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.
  • S004 · premise_and_result_audit — Recompute LEFT affine approach ORIGINAL positive slope bound one plus abs m with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute LEFT affine approach ORIGINAL approach affine constant sum with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Recompute LEFT affine approach ORIGINAL slope times approach center 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

does not exist

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: db333381c8e7311a17c3c3755e1fbec4b9b6714ea59611104d38a33a6eb585fb
  • candidate record SHA-256: d1e707b06b1555bbbf89f2d9dae9b37f0b8a8ec34cd6a0de3d9a409489850d49
  • semantic review receipt SHA-256: acf03b776f4855e3869810bcbecf1116e3a2b11dfb1e2a5dfbcf8135ad24a7d0
  • question-first witness SHA-256: eadbbac3220988b52754f32450fb536d627217306d1ce28a49134f56c21bfa88
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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