![]() |
Mathbox for Alexander van der Vekens |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > Mathboxes > altgsumbc | Structured version Visualization version GIF version |
Description: The sum of binomial coefficients for a fixed positive 𝑁 with alternating signs is zero. Notice that this is not valid for 𝑁 = 0 (since ((-1↑0) · (0C0)) = (1 · 1) = 1). For a proof using Pascal's rule (bcpascm1 48196) instead of the binomial theorem (binom 15863), see altgsumbcALT 48198. (Contributed by AV, 13-Sep-2019.) |
Ref | Expression |
---|---|
altgsumbc | ⊢ (𝑁 ∈ ℕ → Σ𝑘 ∈ (0...𝑁)((-1↑𝑘) · (𝑁C𝑘)) = 0) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 1cnd 11254 | . . . 4 ⊢ (𝑁 ∈ ℕ → 1 ∈ ℂ) | |
2 | negid 11554 | . . . . 5 ⊢ (1 ∈ ℂ → (1 + -1) = 0) | |
3 | 2 | eqcomd 2741 | . . . 4 ⊢ (1 ∈ ℂ → 0 = (1 + -1)) |
4 | 1, 3 | syl 17 | . . 3 ⊢ (𝑁 ∈ ℕ → 0 = (1 + -1)) |
5 | 4 | oveq1d 7446 | . 2 ⊢ (𝑁 ∈ ℕ → (0↑𝑁) = ((1 + -1)↑𝑁)) |
6 | 0exp 14135 | . 2 ⊢ (𝑁 ∈ ℕ → (0↑𝑁) = 0) | |
7 | 1 | negcld 11605 | . . . 4 ⊢ (𝑁 ∈ ℕ → -1 ∈ ℂ) |
8 | nnnn0 12531 | . . . 4 ⊢ (𝑁 ∈ ℕ → 𝑁 ∈ ℕ0) | |
9 | binom 15863 | . . . 4 ⊢ ((1 ∈ ℂ ∧ -1 ∈ ℂ ∧ 𝑁 ∈ ℕ0) → ((1 + -1)↑𝑁) = Σ𝑘 ∈ (0...𝑁)((𝑁C𝑘) · ((1↑(𝑁 − 𝑘)) · (-1↑𝑘)))) | |
10 | 1, 7, 8, 9 | syl3anc 1370 | . . 3 ⊢ (𝑁 ∈ ℕ → ((1 + -1)↑𝑁) = Σ𝑘 ∈ (0...𝑁)((𝑁C𝑘) · ((1↑(𝑁 − 𝑘)) · (-1↑𝑘)))) |
11 | nnz 12632 | . . . . . . . . . 10 ⊢ (𝑁 ∈ ℕ → 𝑁 ∈ ℤ) | |
12 | elfzelz 13561 | . . . . . . . . . 10 ⊢ (𝑘 ∈ (0...𝑁) → 𝑘 ∈ ℤ) | |
13 | zsubcl 12657 | . . . . . . . . . 10 ⊢ ((𝑁 ∈ ℤ ∧ 𝑘 ∈ ℤ) → (𝑁 − 𝑘) ∈ ℤ) | |
14 | 11, 12, 13 | syl2an 596 | . . . . . . . . 9 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (𝑁 − 𝑘) ∈ ℤ) |
15 | 1exp 14129 | . . . . . . . . 9 ⊢ ((𝑁 − 𝑘) ∈ ℤ → (1↑(𝑁 − 𝑘)) = 1) | |
16 | 14, 15 | syl 17 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (1↑(𝑁 − 𝑘)) = 1) |
17 | 16 | oveq1d 7446 | . . . . . . 7 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → ((1↑(𝑁 − 𝑘)) · (-1↑𝑘)) = (1 · (-1↑𝑘))) |
18 | neg1cn 12378 | . . . . . . . . . 10 ⊢ -1 ∈ ℂ | |
19 | 18 | a1i 11 | . . . . . . . . 9 ⊢ (𝑁 ∈ ℕ → -1 ∈ ℂ) |
20 | elfznn0 13657 | . . . . . . . . 9 ⊢ (𝑘 ∈ (0...𝑁) → 𝑘 ∈ ℕ0) | |
21 | expcl 14117 | . . . . . . . . 9 ⊢ ((-1 ∈ ℂ ∧ 𝑘 ∈ ℕ0) → (-1↑𝑘) ∈ ℂ) | |
22 | 19, 20, 21 | syl2an 596 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (-1↑𝑘) ∈ ℂ) |
23 | 22 | mullidd 11277 | . . . . . . 7 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (1 · (-1↑𝑘)) = (-1↑𝑘)) |
24 | 17, 23 | eqtrd 2775 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → ((1↑(𝑁 − 𝑘)) · (-1↑𝑘)) = (-1↑𝑘)) |
25 | 24 | oveq2d 7447 | . . . . 5 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → ((𝑁C𝑘) · ((1↑(𝑁 − 𝑘)) · (-1↑𝑘))) = ((𝑁C𝑘) · (-1↑𝑘))) |
26 | bccl 14358 | . . . . . . . 8 ⊢ ((𝑁 ∈ ℕ0 ∧ 𝑘 ∈ ℤ) → (𝑁C𝑘) ∈ ℕ0) | |
27 | 8, 12, 26 | syl2an 596 | . . . . . . 7 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (𝑁C𝑘) ∈ ℕ0) |
28 | 27 | nn0cnd 12587 | . . . . . 6 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → (𝑁C𝑘) ∈ ℂ) |
29 | 28, 22 | mulcomd 11280 | . . . . 5 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → ((𝑁C𝑘) · (-1↑𝑘)) = ((-1↑𝑘) · (𝑁C𝑘))) |
30 | 25, 29 | eqtrd 2775 | . . . 4 ⊢ ((𝑁 ∈ ℕ ∧ 𝑘 ∈ (0...𝑁)) → ((𝑁C𝑘) · ((1↑(𝑁 − 𝑘)) · (-1↑𝑘))) = ((-1↑𝑘) · (𝑁C𝑘))) |
31 | 30 | sumeq2dv 15735 | . . 3 ⊢ (𝑁 ∈ ℕ → Σ𝑘 ∈ (0...𝑁)((𝑁C𝑘) · ((1↑(𝑁 − 𝑘)) · (-1↑𝑘))) = Σ𝑘 ∈ (0...𝑁)((-1↑𝑘) · (𝑁C𝑘))) |
32 | 10, 31 | eqtrd 2775 | . 2 ⊢ (𝑁 ∈ ℕ → ((1 + -1)↑𝑁) = Σ𝑘 ∈ (0...𝑁)((-1↑𝑘) · (𝑁C𝑘))) |
33 | 5, 6, 32 | 3eqtr3rd 2784 | 1 ⊢ (𝑁 ∈ ℕ → Σ𝑘 ∈ (0...𝑁)((-1↑𝑘) · (𝑁C𝑘)) = 0) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ wa 395 = wceq 1537 ∈ wcel 2106 (class class class)co 7431 ℂcc 11151 0cc0 11153 1c1 11154 + caddc 11156 · cmul 11158 − cmin 11490 -cneg 11491 ℕcn 12264 ℕ0cn0 12524 ℤcz 12611 ...cfz 13544 ↑cexp 14099 Ccbc 14338 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: (None) |
Copyright terms: Public domain | W3C validator |