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Mirrors > Home > MPE Home > Th. List > Mathboxes > nicomachus | Structured version Visualization version GIF version |
Description: Nicomachus's Theorem. The sum of the odd numbers from 𝑁↑2 − 𝑁 + 1 to 𝑁↑2 + 𝑁 − 1 is 𝑁↑3. Proof 2 from https://proofwiki.org/wiki/Nicomachus%27s_Theorem. (Contributed by SN, 21-Mar-2025.) |
Ref | Expression |
---|---|
nicomachus | ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)(((𝑁↑2) − 𝑁) + ((2 · 𝑘) − 1)) = (𝑁↑3)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fzfid 13970 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (1...𝑁) ∈ Fin) | |
2 | nn0cn 12512 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
3 | 2 | adantr 480 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 𝑁 ∈ ℂ) |
4 | 3 | sqcld 14140 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → (𝑁↑2) ∈ ℂ) |
5 | 4, 3 | subcld 11601 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → ((𝑁↑2) − 𝑁) ∈ ℂ) |
6 | 2cnd 12320 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 2 ∈ ℂ) | |
7 | elfznn 13562 | . . . . . . 7 ⊢ (𝑘 ∈ (1...𝑁) → 𝑘 ∈ ℕ) | |
8 | 7 | nncnd 12258 | . . . . . 6 ⊢ (𝑘 ∈ (1...𝑁) → 𝑘 ∈ ℂ) |
9 | 8 | adantl 481 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 𝑘 ∈ ℂ) |
10 | 6, 9 | mulcld 11264 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → (2 · 𝑘) ∈ ℂ) |
11 | 1cnd 11239 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 1 ∈ ℂ) | |
12 | 10, 11 | subcld 11601 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → ((2 · 𝑘) − 1) ∈ ℂ) |
13 | 1, 5, 12 | fsumadd 15718 | . 2 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)(((𝑁↑2) − 𝑁) + ((2 · 𝑘) − 1)) = (Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) + Σ𝑘 ∈ (1...𝑁)((2 · 𝑘) − 1))) |
14 | id 22 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℕ0) | |
15 | 2 | sqcld 14140 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑2) ∈ ℂ) |
16 | 15, 2 | subcld 11601 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁↑2) − 𝑁) ∈ ℂ) |
17 | 14, 16 | fz1sumconst 41869 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) = (𝑁 · ((𝑁↑2) − 𝑁))) |
18 | 2, 15, 2 | subdid 11700 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · ((𝑁↑2) − 𝑁)) = ((𝑁 · (𝑁↑2)) − (𝑁 · 𝑁))) |
19 | df-3 12306 | . . . . . . . 8 ⊢ 3 = (2 + 1) | |
20 | 19 | oveq2i 7431 | . . . . . . 7 ⊢ (𝑁↑3) = (𝑁↑(2 + 1)) |
21 | 2nn0 12519 | . . . . . . . . 9 ⊢ 2 ∈ ℕ0 | |
22 | 21 | a1i 11 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 2 ∈ ℕ0) |
23 | 2, 22 | expp1d 14143 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑(2 + 1)) = ((𝑁↑2) · 𝑁)) |
24 | 20, 23 | eqtrid 2780 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑3) = ((𝑁↑2) · 𝑁)) |
25 | 15, 2 | mulcomd 11265 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → ((𝑁↑2) · 𝑁) = (𝑁 · (𝑁↑2))) |
26 | 24, 25 | eqtr2d 2769 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · (𝑁↑2)) = (𝑁↑3)) |
27 | 2 | sqvald 14139 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑2) = (𝑁 · 𝑁)) |
28 | 27 | eqcomd 2734 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · 𝑁) = (𝑁↑2)) |
29 | 26, 28 | oveq12d 7438 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 · (𝑁↑2)) − (𝑁 · 𝑁)) = ((𝑁↑3) − (𝑁↑2))) |
30 | 17, 18, 29 | 3eqtrd 2772 | . . 3 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) = ((𝑁↑3) − (𝑁↑2))) |
31 | oddnumth 41871 | . . 3 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((2 · 𝑘) − 1) = (𝑁↑2)) | |
32 | 30, 31 | oveq12d 7438 | . 2 ⊢ (𝑁 ∈ ℕ0 → (Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) + Σ𝑘 ∈ (1...𝑁)((2 · 𝑘) − 1)) = (((𝑁↑3) − (𝑁↑2)) + (𝑁↑2))) |
33 | 3nn0 12520 | . . . . 5 ⊢ 3 ∈ ℕ0 | |
34 | 33 | a1i 11 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → 3 ∈ ℕ0) |
35 | 2, 34 | expcld 14142 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑3) ∈ ℂ) |
36 | 35, 15 | npcand 11605 | . 2 ⊢ (𝑁 ∈ ℕ0 → (((𝑁↑3) − (𝑁↑2)) + (𝑁↑2)) = (𝑁↑3)) |
37 | 13, 32, 36 | 3eqtrd 2772 | 1 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)(((𝑁↑2) − 𝑁) + ((2 · 𝑘) − 1)) = (𝑁↑3)) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1534 ∈ wcel 2099 (class class class)co 7420 ℂcc 11136 1c1 11139 + caddc 11141 · cmul 11143 − cmin 11474 2c2 12297 3c3 12298 ℕ0cn0 12502 ...cfz 13516 ↑cexp 14058 Σcsu 15664 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2167 ax-ext 2699 ax-rep 5285 ax-sep 5299 ax-nul 5306 ax-pow 5365 ax-pr 5429 ax-un 7740 ax-inf2 9664 ax-cnex 11194 ax-resscn 11195 ax-1cn 11196 ax-icn 11197 ax-addcl 11198 ax-addrcl 11199 ax-mulcl 11200 ax-mulrcl 11201 ax-mulcom 11202 ax-addass 11203 ax-mulass 11204 ax-distr 11205 ax-i2m1 11206 ax-1ne0 11207 ax-1rid 11208 ax-rnegex 11209 ax-rrecex 11210 ax-cnre 11211 ax-pre-lttri 11212 ax-pre-lttrn 11213 ax-pre-ltadd 11214 ax-pre-mulgt0 11215 ax-pre-sup 11216 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2530 df-eu 2559 df-clab 2706 df-cleq 2720 df-clel 2806 df-nfc 2881 df-ne 2938 df-nel 3044 df-ral 3059 df-rex 3068 df-rmo 3373 df-reu 3374 df-rab 3430 df-v 3473 df-sbc 3777 df-csb 3893 df-dif 3950 df-un 3952 df-in 3954 df-ss 3964 df-pss 3966 df-nul 4324 df-if 4530 df-pw 4605 df-sn 4630 df-pr 4632 df-op 4636 df-uni 4909 df-int 4950 df-iun 4998 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5576 df-eprel 5582 df-po 5590 df-so 5591 df-fr 5633 df-se 5634 df-we 5635 df-xp 5684 df-rel 5685 df-cnv 5686 df-co 5687 df-dm 5688 df-rn 5689 df-res 5690 df-ima 5691 df-pred 6305 df-ord 6372 df-on 6373 df-lim 6374 df-suc 6375 df-iota 6500 df-fun 6550 df-fn 6551 df-f 6552 df-f1 6553 df-fo 6554 df-f1o 6555 df-fv 6556 df-isom 6557 df-riota 7376 df-ov 7423 df-oprab 7424 df-mpo 7425 df-om 7871 df-1st 7993 df-2nd 7994 df-frecs 8286 df-wrecs 8317 df-recs 8391 df-rdg 8430 df-1o 8486 df-er 8724 df-en 8964 df-dom 8965 df-sdom 8966 df-fin 8967 df-sup 9465 df-oi 9533 df-card 9962 df-pnf 11280 df-mnf 11281 df-xr 11282 df-ltxr 11283 df-le 11284 df-sub 11476 df-neg 11477 df-div 11902 df-nn 12243 df-2 12305 df-3 12306 df-n0 12503 df-z 12589 df-uz 12853 df-rp 13007 df-fz 13517 df-fzo 13660 df-seq 13999 df-exp 14059 df-fac 14265 df-bc 14294 df-hash 14322 df-cj 15078 df-re 15079 df-im 15080 df-sqrt 15214 df-abs 15215 df-clim 15464 df-sum 15665 |
This theorem is referenced by: sumcubes 41873 |
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