Mathbox for Thierry Arnoux |
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Mirrors > Home > MPE Home > Th. List > Mathboxes > fib4 | Structured version Visualization version GIF version |
Description: Value of the Fibonacci sequence at index 4. (Contributed by Thierry Arnoux, 25-Apr-2019.) |
Ref | Expression |
---|---|
fib4 | ⊢ (Fibci‘4) = 3 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 3p1e4 11785 | . . 3 ⊢ (3 + 1) = 4 | |
2 | 1 | fveq2i 6676 | . 2 ⊢ (Fibci‘(3 + 1)) = (Fibci‘4) |
3 | 3nn 11719 | . . . 4 ⊢ 3 ∈ ℕ | |
4 | fibp1 31663 | . . . 4 ⊢ (3 ∈ ℕ → (Fibci‘(3 + 1)) = ((Fibci‘(3 − 1)) + (Fibci‘3))) | |
5 | 3, 4 | ax-mp 5 | . . 3 ⊢ (Fibci‘(3 + 1)) = ((Fibci‘(3 − 1)) + (Fibci‘3)) |
6 | 3m1e2 11768 | . . . . . 6 ⊢ (3 − 1) = 2 | |
7 | 6 | fveq2i 6676 | . . . . 5 ⊢ (Fibci‘(3 − 1)) = (Fibci‘2) |
8 | fib2 31664 | . . . . 5 ⊢ (Fibci‘2) = 1 | |
9 | 7, 8 | eqtri 2847 | . . . 4 ⊢ (Fibci‘(3 − 1)) = 1 |
10 | fib3 31665 | . . . 4 ⊢ (Fibci‘3) = 2 | |
11 | 9, 10 | oveq12i 7171 | . . 3 ⊢ ((Fibci‘(3 − 1)) + (Fibci‘3)) = (1 + 2) |
12 | 1p2e3 11783 | . . 3 ⊢ (1 + 2) = 3 | |
13 | 5, 11, 12 | 3eqtri 2851 | . 2 ⊢ (Fibci‘(3 + 1)) = 3 |
14 | 2, 13 | eqtr3i 2849 | 1 ⊢ (Fibci‘4) = 3 |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1536 ∈ wcel 2113 ‘cfv 6358 (class class class)co 7159 1c1 10541 + caddc 10543 − cmin 10873 ℕcn 11641 2c2 11695 3c3 11696 4c4 11697 Fibcicfib 31658 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1969 ax-7 2014 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2160 ax-12 2176 ax-ext 2796 ax-rep 5193 ax-sep 5206 ax-nul 5213 ax-pow 5269 ax-pr 5333 ax-un 7464 ax-inf2 9107 ax-cnex 10596 ax-resscn 10597 ax-1cn 10598 ax-icn 10599 ax-addcl 10600 ax-addrcl 10601 ax-mulcl 10602 ax-mulrcl 10603 ax-mulcom 10604 ax-addass 10605 ax-mulass 10606 ax-distr 10607 ax-i2m1 10608 ax-1ne0 10609 ax-1rid 10610 ax-rnegex 10611 ax-rrecex 10612 ax-cnre 10613 ax-pre-lttri 10614 ax-pre-lttrn 10615 ax-pre-ltadd 10616 ax-pre-mulgt0 10617 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1539 df-ex 1780 df-nf 1784 df-sb 2069 df-mo 2621 df-eu 2653 df-clab 2803 df-cleq 2817 df-clel 2896 df-nfc 2966 df-ne 3020 df-nel 3127 df-ral 3146 df-rex 3147 df-reu 3148 df-rab 3150 df-v 3499 df-sbc 3776 df-csb 3887 df-dif 3942 df-un 3944 df-in 3946 df-ss 3955 df-pss 3957 df-nul 4295 df-if 4471 df-pw 4544 df-sn 4571 df-pr 4573 df-tp 4575 df-op 4577 df-uni 4842 df-int 4880 df-iun 4924 df-br 5070 df-opab 5132 df-mpt 5150 df-tr 5176 df-id 5463 df-eprel 5468 df-po 5477 df-so 5478 df-fr 5517 df-we 5519 df-xp 5564 df-rel 5565 df-cnv 5566 df-co 5567 df-dm 5568 df-rn 5569 df-res 5570 df-ima 5571 df-pred 6151 df-ord 6197 df-on 6198 df-lim 6199 df-suc 6200 df-iota 6317 df-fun 6360 df-fn 6361 df-f 6362 df-f1 6363 df-fo 6364 df-f1o 6365 df-fv 6366 df-riota 7117 df-ov 7162 df-oprab 7163 df-mpo 7164 df-om 7584 df-1st 7692 df-2nd 7693 df-wrecs 7950 df-recs 8011 df-rdg 8049 df-1o 8105 df-oadd 8109 df-er 8292 df-map 8411 df-en 8513 df-dom 8514 df-sdom 8515 df-fin 8516 df-card 9371 df-pnf 10680 df-mnf 10681 df-xr 10682 df-ltxr 10683 df-le 10684 df-sub 10875 df-neg 10876 df-nn 11642 df-2 11703 df-3 11704 df-4 11705 df-n0 11901 df-xnn0 11971 df-z 11985 df-uz 12247 df-rp 12393 df-fz 12896 df-fzo 13037 df-seq 13373 df-hash 13694 df-word 13865 df-lsw 13918 df-concat 13926 df-s1 13953 df-substr 14006 df-pfx 14036 df-s2 14213 df-sseq 31646 df-fib 31659 |
This theorem is referenced by: fib5 31667 fib6 31668 |
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