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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 15552 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝐴 FallFac 𝑁) = ∏𝑛 ∈ (0...(𝑁 − 1))(𝐴 − 𝑛)) | |
2 | 1zzd 12191 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 1 ∈ ℤ) | |
3 | 0zd 12171 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 0 ∈ ℤ) | |
4 | nn0z 12183 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℤ) | |
5 | peano2zm 12203 | . . . . 5 ⊢ (𝑁 ∈ ℤ → (𝑁 − 1) ∈ ℤ) | |
6 | 4, 5 | syl 17 | . . . 4 ⊢ (𝑁 ∈ ℕ0 → (𝑁 − 1) ∈ ℤ) |
7 | 6 | adantl 485 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (𝑁 − 1) ∈ ℤ) |
8 | simpl 486 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → 𝐴 ∈ ℂ) | |
9 | elfznn0 13188 | . . . . 5 ⊢ (𝑛 ∈ (0...(𝑁 − 1)) → 𝑛 ∈ ℕ0) | |
10 | 9 | nn0cnd 12135 | . . . 4 ⊢ (𝑛 ∈ (0...(𝑁 − 1)) → 𝑛 ∈ ℂ) |
11 | subcl 11060 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑛 ∈ ℂ) → (𝐴 − 𝑛) ∈ ℂ) | |
12 | 8, 10, 11 | syl2an 599 | . . 3 ⊢ (((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) ∧ 𝑛 ∈ (0...(𝑁 − 1))) → (𝐴 − 𝑛) ∈ ℂ) |
13 | oveq2 7210 | . . 3 ⊢ (𝑛 = (𝑘 − 1) → (𝐴 − 𝑛) = (𝐴 − (𝑘 − 1))) | |
14 | 2, 3, 7, 12, 13 | fprodshft 15519 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ∏𝑛 ∈ (0...(𝑁 − 1))(𝐴 − 𝑛) = ∏𝑘 ∈ ((0 + 1)...((𝑁 − 1) + 1))(𝐴 − (𝑘 − 1))) |
15 | 0p1e1 11935 | . . . . 5 ⊢ (0 + 1) = 1 | |
16 | 15 | a1i 11 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → (0 + 1) = 1) |
17 | nn0cn 12083 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 𝑁 ∈ ℂ) | |
18 | 1cnd 10811 | . . . . . 6 ⊢ (𝑁 ∈ ℕ0 → 1 ∈ ℂ) | |
19 | 17, 18 | npcand 11176 | . . . . 5 ⊢ (𝑁 ∈ ℕ0 → ((𝑁 − 1) + 1) = 𝑁) |
20 | 19 | adantl 485 | . . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ((𝑁 − 1) + 1) = 𝑁) |
21 | 16, 20 | oveq12d 7220 | . . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ((0 + 1)...((𝑁 − 1) + 1)) = (1...𝑁)) |
22 | 21 | prodeq1d 15464 | . 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 2778 | 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 399 = wceq 1543 ∈ wcel 2110 (class class class)co 7202 ℂcc 10710 0cc0 10712 1c1 10713 + caddc 10715 − cmin 11045 ℕ0cn0 12073 ℤcz 12159 ...cfz 13078 ∏cprod 15448 FallFac cfallfac 15547 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2016 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2158 ax-12 2175 ax-ext 2706 ax-rep 5168 ax-sep 5181 ax-nul 5188 ax-pow 5247 ax-pr 5311 ax-un 7512 ax-inf2 9245 ax-cnex 10768 ax-resscn 10769 ax-1cn 10770 ax-icn 10771 ax-addcl 10772 ax-addrcl 10773 ax-mulcl 10774 ax-mulrcl 10775 ax-mulcom 10776 ax-addass 10777 ax-mulass 10778 ax-distr 10779 ax-i2m1 10780 ax-1ne0 10781 ax-1rid 10782 ax-rnegex 10783 ax-rrecex 10784 ax-cnre 10785 ax-pre-lttri 10786 ax-pre-lttrn 10787 ax-pre-ltadd 10788 ax-pre-mulgt0 10789 ax-pre-sup 10790 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2071 df-mo 2537 df-eu 2566 df-clab 2713 df-cleq 2726 df-clel 2812 df-nfc 2882 df-ne 2936 df-nel 3040 df-ral 3059 df-rex 3060 df-reu 3061 df-rmo 3062 df-rab 3063 df-v 3403 df-sbc 3688 df-csb 3803 df-dif 3860 df-un 3862 df-in 3864 df-ss 3874 df-pss 3876 df-nul 4228 df-if 4430 df-pw 4505 df-sn 4532 df-pr 4534 df-tp 4536 df-op 4538 df-uni 4810 df-int 4850 df-iun 4896 df-br 5044 df-opab 5106 df-mpt 5125 df-tr 5151 df-id 5444 df-eprel 5449 df-po 5457 df-so 5458 df-fr 5498 df-se 5499 df-we 5500 df-xp 5546 df-rel 5547 df-cnv 5548 df-co 5549 df-dm 5550 df-rn 5551 df-res 5552 df-ima 5553 df-pred 6149 df-ord 6205 df-on 6206 df-lim 6207 df-suc 6208 df-iota 6327 df-fun 6371 df-fn 6372 df-f 6373 df-f1 6374 df-fo 6375 df-f1o 6376 df-fv 6377 df-isom 6378 df-riota 7159 df-ov 7205 df-oprab 7206 df-mpo 7207 df-om 7634 df-1st 7750 df-2nd 7751 df-wrecs 8036 df-recs 8097 df-rdg 8135 df-1o 8191 df-er 8380 df-en 8616 df-dom 8617 df-sdom 8618 df-fin 8619 df-sup 9047 df-oi 9115 df-card 9538 df-pnf 10852 df-mnf 10853 df-xr 10854 df-ltxr 10855 df-le 10856 df-sub 11047 df-neg 11048 df-div 11473 df-nn 11814 df-2 11876 df-3 11877 df-n0 12074 df-z 12160 df-uz 12422 df-rp 12570 df-fz 13079 df-fzo 13222 df-seq 13558 df-exp 13619 df-hash 13880 df-cj 14645 df-re 14646 df-im 14647 df-sqrt 14781 df-abs 14782 df-clim 15032 df-prod 15449 df-fallfac 15550 |
This theorem is referenced by: risefallfac 15567 fallfacfwd 15579 |
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