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Question 93: The Finite Expansion Includes Every k from Zero through n

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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P250-0093 · q-20261014-advance-20261109-r05-binomial-theorem-0043

Original question and givens

Use natural exponent n=17, including0, in a commutative coefficient setting. Give (n, coefficient_exponent_rows, boundary).

  • G001 — Use natural exponent n=17, including0, in a commutative coefficient setting. Give (n, coefficient_exponent_rows, boundary).

Definition and scope

n is a nonnegative integer and x,y commute. For n=0 use the polynomial empty-product identity.

Step-by-step derivation

S001 · implies

Before

n=17≥0; x,y commute

After

(x+y)^17 is a finite product of 17 factors

Conditions: none

Choose x or y from each factor; commutativity permits grouping products by the number of y choices.

Step identifiers and dependencies

Rule: finite_product · Uses: G001

S002 · implies

Before

choose exactly 0 of 17 factors to contribute y

After

C(17,0)=355687428096000/(1·355687428096000)=1

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 0 y positions and 17 x positions, giving coefficient 1.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S001

S003 · implies

Before

C(17,0)=1; choose y 0 times

After

1·x^17·y^0

Conditions: none

The x exponent is 17-0=17; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S002

S004 · implies

Before

choose exactly 1 of 17 factors to contribute y

After

C(17,1)=355687428096000/(1·20922789888000)=17

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 1 y positions and 16 x positions, giving coefficient 17.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S003

S005 · implies

Before

C(17,1)=17; choose y 1 times

After

17·x^16·y^1

Conditions: none

The x exponent is 17-1=16; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S004

S006 · implies

Before

choose exactly 2 of 17 factors to contribute y

After

C(17,2)=355687428096000/(2·1307674368000)=136

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 2 y positions and 15 x positions, giving coefficient 136.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S005

S007 · implies

Before

C(17,2)=136; choose y 2 times

After

136·x^15·y^2

Conditions: none

The x exponent is 17-2=15; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S006

S008 · implies

Before

choose exactly 3 of 17 factors to contribute y

After

C(17,3)=355687428096000/(6·87178291200)=680

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 3 y positions and 14 x positions, giving coefficient 680.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S007

S009 · implies

Before

C(17,3)=680; choose y 3 times

After

680·x^14·y^3

Conditions: none

The x exponent is 17-3=14; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S008

S010 · implies

Before

choose exactly 4 of 17 factors to contribute y

After

C(17,4)=355687428096000/(24·6227020800)=2380

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 4 y positions and 13 x positions, giving coefficient 2380.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S009

S011 · implies

Before

C(17,4)=2380; choose y 4 times

After

2380·x^13·y^4

Conditions: none

The x exponent is 17-4=13; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S010

S012 · implies

Before

choose exactly 5 of 17 factors to contribute y

After

C(17,5)=355687428096000/(120·479001600)=6188

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 5 y positions and 12 x positions, giving coefficient 6188.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S011

S013 · implies

Before

C(17,5)=6188; choose y 5 times

After

6188·x^12·y^5

Conditions: none

The x exponent is 17-5=12; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S012

S014 · implies

Before

choose exactly 6 of 17 factors to contribute y

After

C(17,6)=355687428096000/(720·39916800)=12376

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 6 y positions and 11 x positions, giving coefficient 12376.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S013

S015 · implies

Before

C(17,6)=12376; choose y 6 times

After

12376·x^11·y^6

Conditions: none

The x exponent is 17-6=11; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S014

S016 · implies

Before

choose exactly 7 of 17 factors to contribute y

After

C(17,7)=355687428096000/(5040·3628800)=19448

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 7 y positions and 10 x positions, giving coefficient 19448.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S015

S017 · implies

Before

C(17,7)=19448; choose y 7 times

After

19448·x^10·y^7

Conditions: none

The x exponent is 17-7=10; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S016

S018 · implies

Before

choose exactly 8 of 17 factors to contribute y

After

C(17,8)=355687428096000/(40320·362880)=24310

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 8 y positions and 9 x positions, giving coefficient 24310.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S017

S019 · implies

Before

C(17,8)=24310; choose y 8 times

After

24310·x^9·y^8

Conditions: none

The x exponent is 17-8=9; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S018

S020 · implies

Before

choose exactly 9 of 17 factors to contribute y

After

C(17,9)=355687428096000/(362880·40320)=24310

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 9 y positions and 8 x positions, giving coefficient 24310.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S019

S021 · implies

Before

C(17,9)=24310; choose y 9 times

After

24310·x^8·y^9

Conditions: none

The x exponent is 17-9=8; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S020

S022 · implies

Before

choose exactly 10 of 17 factors to contribute y

After

C(17,10)=355687428096000/(3628800·5040)=19448

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 10 y positions and 7 x positions, giving coefficient 19448.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S021

S023 · implies

Before

C(17,10)=19448; choose y 10 times

After

19448·x^7·y^10

Conditions: none

The x exponent is 17-10=7; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S022

S024 · implies

Before

choose exactly 11 of 17 factors to contribute y

After

C(17,11)=355687428096000/(39916800·720)=12376

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 11 y positions and 6 x positions, giving coefficient 12376.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S023

S025 · implies

Before

C(17,11)=12376; choose y 11 times

After

12376·x^6·y^11

Conditions: none

The x exponent is 17-11=6; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S024

S026 · implies

Before

choose exactly 12 of 17 factors to contribute y

After

C(17,12)=355687428096000/(479001600·120)=6188

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 12 y positions and 5 x positions, giving coefficient 6188.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S025

S027 · implies

Before

C(17,12)=6188; choose y 12 times

After

6188·x^5·y^12

Conditions: none

The x exponent is 17-12=5; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S026

S028 · implies

Before

choose exactly 13 of 17 factors to contribute y

After

C(17,13)=355687428096000/(6227020800·24)=2380

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 13 y positions and 4 x positions, giving coefficient 2380.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S027

S029 · implies

Before

C(17,13)=2380; choose y 13 times

After

2380·x^4·y^13

Conditions: none

The x exponent is 17-13=4; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S028

S030 · implies

Before

choose exactly 14 of 17 factors to contribute y

After

C(17,14)=355687428096000/(87178291200·6)=680

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 14 y positions and 3 x positions, giving coefficient 680.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S029

S031 · implies

Before

C(17,14)=680; choose y 14 times

After

680·x^3·y^14

Conditions: none

The x exponent is 17-14=3; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S030

S032 · implies

Before

choose exactly 15 of 17 factors to contribute y

After

C(17,15)=355687428096000/(1307674368000·2)=136

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 15 y positions and 2 x positions, giving coefficient 136.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S031

S033 · implies

Before

C(17,15)=136; choose y 15 times

After

136·x^2·y^15

Conditions: none

The x exponent is 17-15=2; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S032

S034 · implies

Before

choose exactly 16 of 17 factors to contribute y

After

C(17,16)=355687428096000/(20922789888000·1)=17

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 16 y positions and 1 x positions, giving coefficient 17.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S033

S035 · implies

Before

C(17,16)=17; choose y 16 times

After

17·x^1·y^16

Conditions: none

The x exponent is 17-16=1; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S034

S036 · implies

Before

choose exactly 17 of 17 factors to contribute y

After

C(17,17)=355687428096000/(355687428096000·1)=1

Conditions: none

Count orderings of 17 positions and divide by reorderings within the 17 y positions and 0 x positions, giving coefficient 1.

Step identifiers and dependencies

Rule: subset_count · Uses: G001, S035

S037 · implies

Before

C(17,17)=1; choose y 17 times

After

1·x^0·y^17

Conditions: none

The x exponent is 17-17=0; the two exponents still sum to 17.

Step identifiers and dependencies

Rule: group_like_terms · Uses: G001, S036

S038 · implies

Before

all k=0 through 17 have been accounted for

After

(x+y)^17=1·x^17·y^0 + 17·x^16·y^1 + 136·x^15·y^2 + 680·x^14·y^3 + 2380·x^13·y^4 + 6188·x^12·y^5 + 12376·x^11·y^6 + 19448·x^10·y^7 + 24310·x^9·y^8 + 24310·x^8·y^9 + 19448·x^7·y^10 + 12376·x^6·y^11 + 6188·x^5·y^12 + 2380·x^4·y^13 + 680·x^3·y^14 + 136·x^2·y^15 + 17·x^1·y^16 + 1·x^0·y^17

Conditions: none

Every x/y choice belongs to exactly one k class, so this is the complete finite expansion, not just endpoint terms.

Step identifiers and dependencies

Rule: collect_all_terms · Uses: G001, S037

Reverse checks

  • S038 · premise_and_result_audit — There are n+1 coefficient positions, with the complete range of k retained.
  • S037 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S036 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S035 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S034 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S033 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S032 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S031 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S030 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S029 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S028 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S027 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S026 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S025 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S024 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S023 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S022 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S021 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S020 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S019 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S018 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S017 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S016 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S015 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S014 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S013 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S012 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S011 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S010 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S009 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S008 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S007 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S006 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S005 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S004 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S003 · premise_and_result_audit — The answer row is [k,coefficient,x exponent,y exponent]; do not swap the exponent columns.
  • S002 · premise_and_result_audit — Check the coefficient independently with the integer Pascal recurrence, not approximate factorials.
  • S001 · premise_and_result_audit — This is not an infinite expansion for a noninteger power or a claim for noncommuting multiplication.

Result

(17, [[0, 1, 17, 0], [1, 17, 16, 1], [2, 136, 15, 2], [3, 680, 14, 3], [4, 2380, 13, 4], [5, 6188, 12, 5], [6, 12376, 11, 6], [7, 19448, 10, 7], [8, 24310, 9, 8], [9, 24310, 8, 9], [10, 19448, 7, 10], [11, 12376, 6, 11], [12, 6188, 5, 12], [13, 2380, 4, 13], [14, 680, 3, 14], [15, 136, 2, 15], [16, 17, 1, 16], [17, 1, 0, 17]], complete_k_zero_through_n_coefficients)

The full expansion consists of all displayed monomials, in the same order as the answer rows.

This question review and source binding

Review date: 2026-10-24

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

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