Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > ILE Home > Th. List > cosval | GIF version |
Description: Value of the cosine function. (Contributed by NM, 14-Mar-2005.) (Revised by Mario Carneiro, 10-Nov-2013.) |
Ref | Expression |
---|---|
cosval | ⊢ (𝐴 ∈ ℂ → (cos‘𝐴) = (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-icn 7858 | . . . . . . 7 ⊢ i ∈ ℂ | |
2 | 1 | a1i 9 | . . . . . 6 ⊢ (𝐴 ∈ ℂ → i ∈ ℂ) |
3 | id 19 | . . . . . 6 ⊢ (𝐴 ∈ ℂ → 𝐴 ∈ ℂ) | |
4 | 2, 3 | mulcld 7929 | . . . . 5 ⊢ (𝐴 ∈ ℂ → (i · 𝐴) ∈ ℂ) |
5 | efcl 11616 | . . . . 5 ⊢ ((i · 𝐴) ∈ ℂ → (exp‘(i · 𝐴)) ∈ ℂ) | |
6 | 4, 5 | syl 14 | . . . 4 ⊢ (𝐴 ∈ ℂ → (exp‘(i · 𝐴)) ∈ ℂ) |
7 | negicn 8109 | . . . . . . 7 ⊢ -i ∈ ℂ | |
8 | 7 | a1i 9 | . . . . . 6 ⊢ (𝐴 ∈ ℂ → -i ∈ ℂ) |
9 | 8, 3 | mulcld 7929 | . . . . 5 ⊢ (𝐴 ∈ ℂ → (-i · 𝐴) ∈ ℂ) |
10 | efcl 11616 | . . . . 5 ⊢ ((-i · 𝐴) ∈ ℂ → (exp‘(-i · 𝐴)) ∈ ℂ) | |
11 | 9, 10 | syl 14 | . . . 4 ⊢ (𝐴 ∈ ℂ → (exp‘(-i · 𝐴)) ∈ ℂ) |
12 | 6, 11 | addcld 7928 | . . 3 ⊢ (𝐴 ∈ ℂ → ((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) ∈ ℂ) |
13 | 12 | halfcld 9111 | . 2 ⊢ (𝐴 ∈ ℂ → (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2) ∈ ℂ) |
14 | oveq2 5859 | . . . . . 6 ⊢ (𝑥 = 𝐴 → (i · 𝑥) = (i · 𝐴)) | |
15 | 14 | fveq2d 5498 | . . . . 5 ⊢ (𝑥 = 𝐴 → (exp‘(i · 𝑥)) = (exp‘(i · 𝐴))) |
16 | oveq2 5859 | . . . . . 6 ⊢ (𝑥 = 𝐴 → (-i · 𝑥) = (-i · 𝐴)) | |
17 | 16 | fveq2d 5498 | . . . . 5 ⊢ (𝑥 = 𝐴 → (exp‘(-i · 𝑥)) = (exp‘(-i · 𝐴))) |
18 | 15, 17 | oveq12d 5869 | . . . 4 ⊢ (𝑥 = 𝐴 → ((exp‘(i · 𝑥)) + (exp‘(-i · 𝑥))) = ((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴)))) |
19 | 18 | oveq1d 5866 | . . 3 ⊢ (𝑥 = 𝐴 → (((exp‘(i · 𝑥)) + (exp‘(-i · 𝑥))) / 2) = (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2)) |
20 | df-cos 11603 | . . 3 ⊢ cos = (𝑥 ∈ ℂ ↦ (((exp‘(i · 𝑥)) + (exp‘(-i · 𝑥))) / 2)) | |
21 | 19, 20 | fvmptg 5570 | . 2 ⊢ ((𝐴 ∈ ℂ ∧ (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2) ∈ ℂ) → (cos‘𝐴) = (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2)) |
22 | 13, 21 | mpdan 419 | 1 ⊢ (𝐴 ∈ ℂ → (cos‘𝐴) = (((exp‘(i · 𝐴)) + (exp‘(-i · 𝐴))) / 2)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 = wceq 1348 ∈ wcel 2141 ‘cfv 5196 (class class class)co 5851 ℂcc 7761 ici 7765 + caddc 7766 · cmul 7768 -cneg 8080 / cdiv 8578 2c2 8918 expce 11594 cosccos 11597 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 609 ax-in2 610 ax-io 704 ax-5 1440 ax-7 1441 ax-gen 1442 ax-ie1 1486 ax-ie2 1487 ax-8 1497 ax-10 1498 ax-11 1499 ax-i12 1500 ax-bndl 1502 ax-4 1503 ax-17 1519 ax-i9 1523 ax-ial 1527 ax-i5r 1528 ax-13 2143 ax-14 2144 ax-ext 2152 ax-coll 4102 ax-sep 4105 ax-nul 4113 ax-pow 4158 ax-pr 4192 ax-un 4416 ax-setind 4519 ax-iinf 4570 ax-cnex 7854 ax-resscn 7855 ax-1cn 7856 ax-1re 7857 ax-icn 7858 ax-addcl 7859 ax-addrcl 7860 ax-mulcl 7861 ax-mulrcl 7862 ax-addcom 7863 ax-mulcom 7864 ax-addass 7865 ax-mulass 7866 ax-distr 7867 ax-i2m1 7868 ax-0lt1 7869 ax-1rid 7870 ax-0id 7871 ax-rnegex 7872 ax-precex 7873 ax-cnre 7874 ax-pre-ltirr 7875 ax-pre-ltwlin 7876 ax-pre-lttrn 7877 ax-pre-apti 7878 ax-pre-ltadd 7879 ax-pre-mulgt0 7880 ax-pre-mulext 7881 ax-arch 7882 ax-caucvg 7883 |
This theorem depends on definitions: df-bi 116 df-dc 830 df-3or 974 df-3an 975 df-tru 1351 df-fal 1354 df-nf 1454 df-sb 1756 df-eu 2022 df-mo 2023 df-clab 2157 df-cleq 2163 df-clel 2166 df-nfc 2301 df-ne 2341 df-nel 2436 df-ral 2453 df-rex 2454 df-reu 2455 df-rmo 2456 df-rab 2457 df-v 2732 df-sbc 2956 df-csb 3050 df-dif 3123 df-un 3125 df-in 3127 df-ss 3134 df-nul 3415 df-if 3526 df-pw 3566 df-sn 3587 df-pr 3588 df-op 3590 df-uni 3795 df-int 3830 df-iun 3873 df-br 3988 df-opab 4049 df-mpt 4050 df-tr 4086 df-id 4276 df-po 4279 df-iso 4280 df-iord 4349 df-on 4351 df-ilim 4352 df-suc 4354 df-iom 4573 df-xp 4615 df-rel 4616 df-cnv 4617 df-co 4618 df-dm 4619 df-rn 4620 df-res 4621 df-ima 4622 df-iota 5158 df-fun 5198 df-fn 5199 df-f 5200 df-f1 5201 df-fo 5202 df-f1o 5203 df-fv 5204 df-isom 5205 df-riota 5807 df-ov 5854 df-oprab 5855 df-mpo 5856 df-1st 6117 df-2nd 6118 df-recs 6282 df-irdg 6347 df-frec 6368 df-1o 6393 df-oadd 6397 df-er 6510 df-en 6716 df-dom 6717 df-fin 6718 df-pnf 7945 df-mnf 7946 df-xr 7947 df-ltxr 7948 df-le 7949 df-sub 8081 df-neg 8082 df-reap 8483 df-ap 8490 df-div 8579 df-inn 8868 df-2 8926 df-3 8927 df-4 8928 df-n0 9125 df-z 9202 df-uz 9477 df-q 9568 df-rp 9600 df-ico 9840 df-fz 9955 df-fzo 10088 df-seqfrec 10391 df-exp 10465 df-fac 10649 df-ihash 10699 df-cj 10795 df-re 10796 df-im 10797 df-rsqrt 10951 df-abs 10952 df-clim 11231 df-sumdc 11306 df-ef 11600 df-cos 11603 |
This theorem is referenced by: tanval2ap 11665 tanval3ap 11666 recosval 11668 cosneg 11679 efival 11684 cosadd 11689 cosper 13486 |
Copyright terms: Public domain | W3C validator |