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Mirrors > Home > MPE Home > Th. List > fallfacval2 | Structured version Visualization version GIF version |
Description: One-based value of falling factorial. (Contributed by Scott Fenton, 15-Jan-2018.) |
Ref | Expression |
---|---|
fallfacval2 | ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ (1...𝑁)(𝐴 − (𝑘 − 1))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fallfacval 15980 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑛 ∈ (0...(𝑁 − 1))(𝐴 − 𝑛)) | |
2 | 1zzd 12618 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 1 ∈ ℤ) | |
3 | 0zd 12595 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 0 ∈ ℤ) | |
4 | nn0z 12608 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
5 | peano2zm 12630 | . . . . 5 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
6 | 4, 5 | syl 17 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 − 1) ∈ ℤ) |
7 | 6 | adantl 480 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝑁 − 1) ∈ ℤ) |
8 | simpl 481 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 𝐴 ∈ ℂ) | |
9 | elfznn0 13621 | . . . . 5 ⊢ (𝑛 ∈ (0...(𝑁 − 1)) → 𝑛 ∈ ℕ0) | |
10 | 9 | nn0cnd 12559 | . . . 4 ⊢ (𝑛 ∈ (0...(𝑁 − 1)) → 𝑛 ∈ ℂ) |
11 | subcl 11484 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑛 ∈ ℂ) → (𝐴 − 𝑛) ∈ ℂ) | |
12 | 8, 10, 11 | syl2an 594 | . . 3 ⊢ (((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) ∧ 𝑛 ∈ (0...(𝑁 − 1))) → (𝐴 − 𝑛) ∈ ℂ) |
13 | oveq2 7421 | . . 3 ⊢ (𝑛 = (𝑘 − 1) → (𝐴 − 𝑛) = (𝐴 − (𝑘 − 1))) | |
14 | 2, 3, 7, 12, 13 | fprodshft 15947 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ∏𝑛 ∈ (0...(𝑁 − 1))(𝐴 − 𝑛) = ∏𝑘 ∈ ((0 + 1)...((𝑁 − 1) + 1))(𝐴 − (𝑘 − 1))) |
15 | 0p1e1 12359 | . . . . 5 ⊢ (0 + 1) = 1 | |
16 | 15 | a1i 11 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (0 + 1) = 1) |
17 | nn0cn 12507 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
18 | 1cnd 11234 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 1 ∈ ℂ) | |
19 | 17, 18 | npcand 11600 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) + 1) = 𝑁) |
20 | 19 | adantl 480 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ((𝑁 − 1) + 1) = 𝑁) |
21 | 16, 20 | oveq12d 7431 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ((0 + 1)...((𝑁 − 1) + 1)) = (1...𝑁)) |
22 | 21 | prodeq1d 15892 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ∏𝑘 ∈ ((0 + 1)...((𝑁 − 1) + 1))(𝐴 − (𝑘 − 1)) = ∏𝑘 ∈ (1...𝑁)(𝐴 − (𝑘 − 1))) |
23 | 1, 14, 22 | 3eqtrd 2769 | 1 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑘 ∈ (1...𝑁)(𝐴 − (𝑘 − 1))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 394 = wceq 1533 ∈ wcel 2098 (class class class)co 7413 ℂcc 11131 0cc0 11133 1c1 11134 + caddc 11136 − cmin 11469 ℕ0cn0 12497 ℤcz 12583 ...cfz 13511 ∏cprod 15876 FallFac cfallfac 15975 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2166 ax-ext 2696 ax-rep 5281 ax-sep 5295 ax-nul 5302 ax-pow 5360 ax-pr 5424 ax-un 7735 ax-inf2 9659 ax-cnex 11189 ax-resscn 11190 ax-1cn 11191 ax-icn 11192 ax-addcl 11193 ax-addrcl 11194 ax-mulcl 11195 ax-mulrcl 11196 ax-mulcom 11197 ax-addass 11198 ax-mulass 11199 ax-distr 11200 ax-i2m1 11201 ax-1ne0 11202 ax-1rid 11203 ax-rnegex 11204 ax-rrecex 11205 ax-cnre 11206 ax-pre-lttri 11207 ax-pre-lttrn 11208 ax-pre-ltadd 11209 ax-pre-mulgt0 11210 ax-pre-sup 11211 |
This theorem depends on definitions: df-bi 206 df-an 395 df-or 846 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2528 df-eu 2557 df-clab 2703 df-cleq 2717 df-clel 2802 df-nfc 2877 df-ne 2931 df-nel 3037 df-ral 3052 df-rex 3061 df-rmo 3364 df-reu 3365 df-rab 3420 df-v 3465 df-sbc 3771 df-csb 3887 df-dif 3944 df-un 3946 df-in 3948 df-ss 3958 df-pss 3961 df-nul 4320 df-if 4526 df-pw 4601 df-sn 4626 df-pr 4628 df-op 4632 df-uni 4905 df-int 4946 df-iun 4994 df-br 5145 df-opab 5207 df-mpt 5228 df-tr 5262 df-id 5571 df-eprel 5577 df-po 5585 df-so 5586 df-fr 5628 df-se 5629 df-we 5630 df-xp 5679 df-rel 5680 df-cnv 5681 df-co 5682 df-dm 5683 df-rn 5684 df-res 5685 df-ima 5686 df-pred 6301 df-ord 6368 df-on 6369 df-lim 6370 df-suc 6371 df-iota 6495 df-fun 6545 df-fn 6546 df-f 6547 df-f1 6548 df-fo 6549 df-f1o 6550 df-fv 6551 df-isom 6552 df-riota 7369 df-ov 7416 df-oprab 7417 df-mpo 7418 df-om 7866 df-1st 7987 df-2nd 7988 df-frecs 8280 df-wrecs 8311 df-recs 8385 df-rdg 8424 df-1o 8480 df-er 8718 df-en 8958 df-dom 8959 df-sdom 8960 df-fin 8961 df-sup 9460 df-oi 9528 df-card 9957 df-pnf 11275 df-mnf 11276 df-xr 11277 df-ltxr 11278 df-le 11279 df-sub 11471 df-neg 11472 df-div 11897 df-nn 12238 df-2 12300 df-3 12301 df-n0 12498 df-z 12584 df-uz 12848 df-rp 13002 df-fz 13512 df-fzo 13655 df-seq 13994 df-exp 14054 df-hash 14317 df-cj 15073 df-re 15074 df-im 15075 df-sqrt 15209 df-abs 15210 df-clim 15459 df-prod 15877 df-fallfac 15978 |
This theorem is referenced by: risefallfac 15995 fallfacfwd 16007 |
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