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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 14011 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (1...𝑁) ∈ Fin) | |
2 | nn0cn 12534 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
3 | 2 | adantr 480 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 𝑁 ∈ ℂ) |
4 | 3 | sqcld 14181 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → (𝑁↑2) ∈ ℂ) |
5 | 4, 3 | subcld 11618 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → ((𝑁↑2) − 𝑁) ∈ ℂ) |
6 | 2cnd 12342 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 2 ∈ ℂ) | |
7 | elfznn 13590 | . . . . . . 7 ⊢ (𝑘 ∈ (1...𝑁) → 𝑘 ∈ ℕ) | |
8 | 7 | nncnd 12280 | . . . . . 6 ⊢ (𝑘 ∈ (1...𝑁) → 𝑘 ∈ ℂ) |
9 | 8 | adantl 481 | . . . . 5 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 𝑘 ∈ ℂ) |
10 | 6, 9 | mulcld 11279 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → (2 · 𝑘) ∈ ℂ) |
11 | 1cnd 11254 | . . . 4 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → 1 ∈ ℂ) | |
12 | 10, 11 | subcld 11618 | . . 3 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ (1...𝑁)) → ((2 · 𝑘) − 1) ∈ ℂ) |
13 | 1, 5, 12 | fsumadd 15773 | . 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 14181 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑2) ∈ ℂ) |
16 | 15, 2 | subcld 11618 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁↑2) − 𝑁) ∈ ℂ) |
17 | 14, 16 | fz1sumconst 42322 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) = (𝑁 · ((𝑁↑2) − 𝑁))) |
18 | 2, 15, 2 | subdid 11717 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · ((𝑁↑2) − 𝑁)) = ((𝑁 · (𝑁↑2)) − (𝑁 · 𝑁))) |
19 | df-3 12328 | . . . . . . . 8 ⊢ 3 = (2 + 1) | |
20 | 19 | oveq2i 7442 | . . . . . . 7 ⊢ (𝑁↑3) = (𝑁↑(2 + 1)) |
21 | 2nn0 12541 | . . . . . . . . 9 ⊢ 2 ∈ ℕ0 | |
22 | 21 | a1i 11 | . . . . . . . 8 ⊢ (𝑁 ∈ ℕ0 → 2 ∈ ℕ0) |
23 | 2, 22 | expp1d 14184 | . . . . . . 7 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑(2 + 1)) = ((𝑁↑2) · 𝑁)) |
24 | 20, 23 | eqtrid 2787 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑3) = ((𝑁↑2) · 𝑁)) |
25 | 15, 2 | mulcomd 11280 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → ((𝑁↑2) · 𝑁) = (𝑁 · (𝑁↑2))) |
26 | 24, 25 | eqtr2d 2776 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · (𝑁↑2)) = (𝑁↑3)) |
27 | 2 | sqvald 14180 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑2) = (𝑁 · 𝑁)) |
28 | 27 | eqcomd 2741 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → (𝑁 · 𝑁) = (𝑁↑2)) |
29 | 26, 28 | oveq12d 7449 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 · (𝑁↑2)) − (𝑁 · 𝑁)) = ((𝑁↑3) − (𝑁↑2))) |
30 | 17, 18, 29 | 3eqtrd 2779 | . . 3 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) = ((𝑁↑3) − (𝑁↑2))) |
31 | oddnumth 42324 | . . 3 ⊢ (𝑁 ∈ ℕ0 → Σ𝑘 ∈ (1...𝑁)((2 · 𝑘) − 1) = (𝑁↑2)) | |
32 | 30, 31 | oveq12d 7449 | . 2 ⊢ (𝑁 ∈ ℕ0 → (Σ𝑘 ∈ (1...𝑁)((𝑁↑2) − 𝑁) + Σ𝑘 ∈ (1...𝑁)((2 · 𝑘) − 1)) = (((𝑁↑3) − (𝑁↑2)) + (𝑁↑2))) |
33 | 3nn0 12542 | . . . . 5 ⊢ 3 ∈ ℕ0 | |
34 | 33 | a1i 11 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → 3 ∈ ℕ0) |
35 | 2, 34 | expcld 14183 | . . 3 ⊢ (𝑁 ∈ ℕ0 → (𝑁↑3) ∈ ℂ) |
36 | 35, 15 | npcand 11622 | . 2 ⊢ (𝑁 ∈ ℕ0 → (((𝑁↑3) − (𝑁↑2)) + (𝑁↑2)) = (𝑁↑3)) |
37 | 13, 32, 36 | 3eqtrd 2779 | 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 1537 ∈ wcel 2106 (class class class)co 7431 ℂcc 11151 1c1 11154 + caddc 11156 · cmul 11158 − cmin 11490 2c2 12319 3c3 12320 ℕ0cn0 12524 ...cfz 13544 ↑cexp 14099 Σcsu 15719 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1908 ax-6 1965 ax-7 2005 ax-8 2108 ax-9 2116 ax-10 2139 ax-11 2155 ax-12 2175 ax-ext 2706 ax-rep 5285 ax-sep 5302 ax-nul 5312 ax-pow 5371 ax-pr 5438 ax-un 7754 ax-inf2 9679 ax-cnex 11209 ax-resscn 11210 ax-1cn 11211 ax-icn 11212 ax-addcl 11213 ax-addrcl 11214 ax-mulcl 11215 ax-mulrcl 11216 ax-mulcom 11217 ax-addass 11218 ax-mulass 11219 ax-distr 11220 ax-i2m1 11221 ax-1ne0 11222 ax-1rid 11223 ax-rnegex 11224 ax-rrecex 11225 ax-cnre 11226 ax-pre-lttri 11227 ax-pre-lttrn 11228 ax-pre-ltadd 11229 ax-pre-mulgt0 11230 ax-pre-sup 11231 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1540 df-fal 1550 df-ex 1777 df-nf 1781 df-sb 2063 df-mo 2538 df-eu 2567 df-clab 2713 df-cleq 2727 df-clel 2814 df-nfc 2890 df-ne 2939 df-nel 3045 df-ral 3060 df-rex 3069 df-rmo 3378 df-reu 3379 df-rab 3434 df-v 3480 df-sbc 3792 df-csb 3909 df-dif 3966 df-un 3968 df-in 3970 df-ss 3980 df-pss 3983 df-nul 4340 df-if 4532 df-pw 4607 df-sn 4632 df-pr 4634 df-op 4638 df-uni 4913 df-int 4952 df-iun 4998 df-br 5149 df-opab 5211 df-mpt 5232 df-tr 5266 df-id 5583 df-eprel 5589 df-po 5597 df-so 5598 df-fr 5641 df-se 5642 df-we 5643 df-xp 5695 df-rel 5696 df-cnv 5697 df-co 5698 df-dm 5699 df-rn 5700 df-res 5701 df-ima 5702 df-pred 6323 df-ord 6389 df-on 6390 df-lim 6391 df-suc 6392 df-iota 6516 df-fun 6565 df-fn 6566 df-f 6567 df-f1 6568 df-fo 6569 df-f1o 6570 df-fv 6571 df-isom 6572 df-riota 7388 df-ov 7434 df-oprab 7435 df-mpo 7436 df-om 7888 df-1st 8013 df-2nd 8014 df-frecs 8305 df-wrecs 8336 df-recs 8410 df-rdg 8449 df-1o 8505 df-er 8744 df-en 8985 df-dom 8986 df-sdom 8987 df-fin 8988 df-sup 9480 df-oi 9548 df-card 9977 df-pnf 11295 df-mnf 11296 df-xr 11297 df-ltxr 11298 df-le 11299 df-sub 11492 df-neg 11493 df-div 11919 df-nn 12265 df-2 12327 df-3 12328 df-n0 12525 df-z 12612 df-uz 12877 df-rp 13033 df-fz 13545 df-fzo 13692 df-seq 14040 df-exp 14100 df-fac 14310 df-bc 14339 df-hash 14367 df-cj 15135 df-re 15136 df-im 15137 df-sqrt 15271 df-abs 15272 df-clim 15521 df-sum 15720 |
This theorem is referenced by: sumcubes 42326 |
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