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Mirrors > Home > MPE Home > Th. List > 4bc2eq6 | Structured version Visualization version GIF version |
Description: The value of four choose two. (Contributed by Scott Fenton, 9-Jan-2017.) |
Ref | Expression |
---|---|
4bc2eq6 | ⊢ (4C2) = 6 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0z 12152 | . . . . 5 ⊢ 0 ∈ ℤ | |
2 | 4z 12176 | . . . . 5 ⊢ 4 ∈ ℤ | |
3 | 2z 12174 | . . . . 5 ⊢ 2 ∈ ℤ | |
4 | 1, 2, 3 | 3pm3.2i 1341 | . . . 4 ⊢ (0 ∈ ℤ ∧ 4 ∈ ℤ ∧ 2 ∈ ℤ) |
5 | 0le2 11897 | . . . . 5 ⊢ 0 ≤ 2 | |
6 | 2re 11869 | . . . . . 6 ⊢ 2 ∈ ℝ | |
7 | 4re 11879 | . . . . . 6 ⊢ 4 ∈ ℝ | |
8 | 2lt4 11970 | . . . . . 6 ⊢ 2 < 4 | |
9 | 6, 7, 8 | ltleii 10920 | . . . . 5 ⊢ 2 ≤ 4 |
10 | 5, 9 | pm3.2i 474 | . . . 4 ⊢ (0 ≤ 2 ∧ 2 ≤ 4) |
11 | elfz4 13070 | . . . 4 ⊢ (((0 ∈ ℤ ∧ 4 ∈ ℤ ∧ 2 ∈ ℤ) ∧ (0 ≤ 2 ∧ 2 ≤ 4)) → 2 ∈ (0...4)) | |
12 | 4, 10, 11 | mp2an 692 | . . 3 ⊢ 2 ∈ (0...4) |
13 | bcval2 13836 | . . 3 ⊢ (2 ∈ (0...4) → (4C2) = ((!‘4) / ((!‘(4 − 2)) · (!‘2)))) | |
14 | 12, 13 | ax-mp 5 | . 2 ⊢ (4C2) = ((!‘4) / ((!‘(4 − 2)) · (!‘2))) |
15 | 3nn0 12073 | . . . . . 6 ⊢ 3 ∈ ℕ0 | |
16 | facp1 13809 | . . . . . 6 ⊢ (3 ∈ ℕ0 → (!‘(3 + 1)) = ((!‘3) · (3 + 1))) | |
17 | 15, 16 | ax-mp 5 | . . . . 5 ⊢ (!‘(3 + 1)) = ((!‘3) · (3 + 1)) |
18 | df-4 11860 | . . . . . 6 ⊢ 4 = (3 + 1) | |
19 | 18 | fveq2i 6698 | . . . . 5 ⊢ (!‘4) = (!‘(3 + 1)) |
20 | 18 | oveq2i 7202 | . . . . 5 ⊢ ((!‘3) · 4) = ((!‘3) · (3 + 1)) |
21 | 17, 19, 20 | 3eqtr4i 2769 | . . . 4 ⊢ (!‘4) = ((!‘3) · 4) |
22 | 4cn 11880 | . . . . . . . . 9 ⊢ 4 ∈ ℂ | |
23 | 2cn 11870 | . . . . . . . . 9 ⊢ 2 ∈ ℂ | |
24 | 2p2e4 11930 | . . . . . . . . 9 ⊢ (2 + 2) = 4 | |
25 | 22, 23, 23, 24 | subaddrii 11132 | . . . . . . . 8 ⊢ (4 − 2) = 2 |
26 | 25 | fveq2i 6698 | . . . . . . 7 ⊢ (!‘(4 − 2)) = (!‘2) |
27 | fac2 13810 | . . . . . . 7 ⊢ (!‘2) = 2 | |
28 | 26, 27 | eqtri 2759 | . . . . . 6 ⊢ (!‘(4 − 2)) = 2 |
29 | 28, 27 | oveq12i 7203 | . . . . 5 ⊢ ((!‘(4 − 2)) · (!‘2)) = (2 · 2) |
30 | 2t2e4 11959 | . . . . 5 ⊢ (2 · 2) = 4 | |
31 | 29, 30 | eqtri 2759 | . . . 4 ⊢ ((!‘(4 − 2)) · (!‘2)) = 4 |
32 | 21, 31 | oveq12i 7203 | . . 3 ⊢ ((!‘4) / ((!‘(4 − 2)) · (!‘2))) = (((!‘3) · 4) / 4) |
33 | faccl 13814 | . . . . . . 7 ⊢ (3 ∈ ℕ0 → (!‘3) ∈ ℕ) | |
34 | 15, 33 | ax-mp 5 | . . . . . 6 ⊢ (!‘3) ∈ ℕ |
35 | 34 | nncni 11805 | . . . . 5 ⊢ (!‘3) ∈ ℂ |
36 | 4ne0 11903 | . . . . 5 ⊢ 4 ≠ 0 | |
37 | 35, 22, 36 | divcan4i 11544 | . . . 4 ⊢ (((!‘3) · 4) / 4) = (!‘3) |
38 | fac3 13811 | . . . 4 ⊢ (!‘3) = 6 | |
39 | 37, 38 | eqtri 2759 | . . 3 ⊢ (((!‘3) · 4) / 4) = 6 |
40 | 32, 39 | eqtri 2759 | . 2 ⊢ ((!‘4) / ((!‘(4 − 2)) · (!‘2))) = 6 |
41 | 14, 40 | eqtri 2759 | 1 ⊢ (4C2) = 6 |
Colors of variables: wff setvar class |
Syntax hints: ∧ wa 399 ∧ w3a 1089 = wceq 1543 ∈ wcel 2112 class class class wbr 5039 ‘cfv 6358 (class class class)co 7191 0cc0 10694 1c1 10695 + caddc 10697 · cmul 10699 ≤ cle 10833 − cmin 11027 / cdiv 11454 ℕcn 11795 2c2 11850 3c3 11851 4c4 11852 6c6 11854 ℕ0cn0 12055 ℤcz 12141 ...cfz 13060 !cfa 13804 Ccbc 13833 |
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 2018 ax-8 2114 ax-9 2122 ax-10 2143 ax-11 2160 ax-12 2177 ax-ext 2708 ax-sep 5177 ax-nul 5184 ax-pow 5243 ax-pr 5307 ax-un 7501 ax-cnex 10750 ax-resscn 10751 ax-1cn 10752 ax-icn 10753 ax-addcl 10754 ax-addrcl 10755 ax-mulcl 10756 ax-mulrcl 10757 ax-mulcom 10758 ax-addass 10759 ax-mulass 10760 ax-distr 10761 ax-i2m1 10762 ax-1ne0 10763 ax-1rid 10764 ax-rnegex 10765 ax-rrecex 10766 ax-cnre 10767 ax-pre-lttri 10768 ax-pre-lttrn 10769 ax-pre-ltadd 10770 ax-pre-mulgt0 10771 |
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 2073 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2728 df-clel 2809 df-nfc 2879 df-ne 2933 df-nel 3037 df-ral 3056 df-rex 3057 df-reu 3058 df-rmo 3059 df-rab 3060 df-v 3400 df-sbc 3684 df-csb 3799 df-dif 3856 df-un 3858 df-in 3860 df-ss 3870 df-pss 3872 df-nul 4224 df-if 4426 df-pw 4501 df-sn 4528 df-pr 4530 df-tp 4532 df-op 4534 df-uni 4806 df-iun 4892 df-br 5040 df-opab 5102 df-mpt 5121 df-tr 5147 df-id 5440 df-eprel 5445 df-po 5453 df-so 5454 df-fr 5494 df-we 5496 df-xp 5542 df-rel 5543 df-cnv 5544 df-co 5545 df-dm 5546 df-rn 5547 df-res 5548 df-ima 5549 df-pred 6140 df-ord 6194 df-on 6195 df-lim 6196 df-suc 6197 df-iota 6316 df-fun 6360 df-fn 6361 df-f 6362 df-f1 6363 df-fo 6364 df-f1o 6365 df-fv 6366 df-riota 7148 df-ov 7194 df-oprab 7195 df-mpo 7196 df-om 7623 df-1st 7739 df-2nd 7740 df-wrecs 8025 df-recs 8086 df-rdg 8124 df-er 8369 df-en 8605 df-dom 8606 df-sdom 8607 df-pnf 10834 df-mnf 10835 df-xr 10836 df-ltxr 10837 df-le 10838 df-sub 11029 df-neg 11030 df-div 11455 df-nn 11796 df-2 11858 df-3 11859 df-4 11860 df-5 11861 df-6 11862 df-n0 12056 df-z 12142 df-uz 12404 df-fz 13061 df-seq 13540 df-fac 13805 df-bc 13834 |
This theorem is referenced by: bpoly4 15584 ex-bc 28489 5bc2eq10 39767 |
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