onetansqsecsq - Mathbox for David A. Wheeler

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Theorem onetansqsecsq 47806

Description: Prove the tangent squared secant squared identity (1 + ((tan A ) ^ 2 ) ) = ( ( sec 𝐴)↑2)). (Contributed by David A. Wheeler, 25-May-2015.)

**Assertion**
Ref	Expression
onetansqsecsq	⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (1 + ((tan‘𝐴)↑2)) = ((sec‘𝐴)↑2))

**Proof of Theorem onetansqsecsq**
Step	Hyp	Ref	Expression
1		coscl 16070	. . . . . . . . . 10 ⊢ (𝐴 ∈ ℂ → (cos‘𝐴) ∈ ℂ)
2		sqeq0 14085	. . . . . . . . . 10 ⊢ ((cos‘𝐴) ∈ ℂ → (((cos‘𝐴)↑2) = 0 ↔ (cos‘𝐴) = 0))
3	1, 2	syl 17	. . . . . . . . 9 ⊢ (𝐴 ∈ ℂ → (((cos‘𝐴)↑2) = 0 ↔ (cos‘𝐴) = 0))
4	3	necon3bid 2986	. . . . . . . 8 ⊢ (𝐴 ∈ ℂ → (((cos‘𝐴)↑2) ≠ 0 ↔ (cos‘𝐴) ≠ 0))
5	4	biimpar 479	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((cos‘𝐴)↑2) ≠ 0)
6	1	sqcld 14109	. . . . . . . 8 ⊢ (𝐴 ∈ ℂ → ((cos‘𝐴)↑2) ∈ ℂ)
7		divid 11901	. . . . . . . 8 ⊢ ((((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0) → (((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) = 1)
8	6, 7	sylan 581	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0) → (((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) = 1)
9	5, 8	syldan 592	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) = 1)
10	9	eqcomd 2739	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → 1 = (((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)))
11		tanval 16071	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (tan‘𝐴) = ((sin‘𝐴) / (cos‘𝐴)))
12	11	oveq1d 7424	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((tan‘𝐴)↑2) = (((sin‘𝐴) / (cos‘𝐴))↑2))
13		2nn0 12489	. . . . . . . . . 10 ⊢ 2 ∈ ℕ₀
14		sincl 16069	. . . . . . . . . . 11 ⊢ (𝐴 ∈ ℂ → (sin‘𝐴) ∈ ℂ)
15		expdiv 14079	. . . . . . . . . . 11 ⊢ (((sin‘𝐴) ∈ ℂ ∧ ((cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0) ∧ 2 ∈ ℕ₀) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
16	14, 15	syl3an1 1164	. . . . . . . . . 10 ⊢ ((𝐴 ∈ ℂ ∧ ((cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0) ∧ 2 ∈ ℕ₀) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
17	13, 16	mp3an3 1451	. . . . . . . . 9 ⊢ ((𝐴 ∈ ℂ ∧ ((cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0)) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
18	17	3impb 1116	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
19	1, 18	syl3an2 1165	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
20	19	3anidm12 1420	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (((sin‘𝐴) / (cos‘𝐴))↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
21	12, 20	eqtrd 2773	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((tan‘𝐴)↑2) = (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2)))
22	10, 21	oveq12d 7427	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (1 + ((tan‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
23	14	sqcld 14109	. . . . . . . . . 10 ⊢ (𝐴 ∈ ℂ → ((sin‘𝐴)↑2) ∈ ℂ)
24		divdir 11897	. . . . . . . . . . 11 ⊢ ((((cos‘𝐴)↑2) ∈ ℂ ∧ ((sin‘𝐴)↑2) ∈ ℂ ∧ (((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0)) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
25	6, 24	syl3an1 1164	. . . . . . . . . 10 ⊢ ((𝐴 ∈ ℂ ∧ ((sin‘𝐴)↑2) ∈ ℂ ∧ (((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0)) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
26	23, 25	syl3an2 1165	. . . . . . . . 9 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ∈ ℂ ∧ (((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0)) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
27	26	3anidm12 1420	. . . . . . . 8 ⊢ ((𝐴 ∈ ℂ ∧ (((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0)) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
28	27	3impb 1116	. . . . . . 7 ⊢ ((𝐴 ∈ ℂ ∧ ((cos‘𝐴)↑2) ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
29	6, 28	syl3an2 1165	. . . . . 6 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
30	29	3anidm12 1420	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ ((cos‘𝐴)↑2) ≠ 0) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
31	5, 30	syldan 592	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = ((((cos‘𝐴)↑2) / ((cos‘𝐴)↑2)) + (((sin‘𝐴)↑2) / ((cos‘𝐴)↑2))))
32	22, 31	eqtr4d 2776	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (1 + ((tan‘𝐴)↑2)) = ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)))
33	23, 6	addcomd 11416	. . . . . 6 ⊢ (𝐴 ∈ ℂ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = (((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)))
34		sincossq 16119	. . . . . 6 ⊢ (𝐴 ∈ ℂ → (((sin‘𝐴)↑2) + ((cos‘𝐴)↑2)) = 1)
35	33, 34	eqtr3d 2775	. . . . 5 ⊢ (𝐴 ∈ ℂ → (((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) = 1)
36	35	oveq1d 7424	. . . 4 ⊢ (𝐴 ∈ ℂ → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = (1 / ((cos‘𝐴)↑2)))
37	36	adantr 482	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((((cos‘𝐴)↑2) + ((sin‘𝐴)↑2)) / ((cos‘𝐴)↑2)) = (1 / ((cos‘𝐴)↑2)))
38	32, 37	eqtrd 2773	. 2 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (1 + ((tan‘𝐴)↑2)) = (1 / ((cos‘𝐴)↑2)))
39		secval 47792	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (sec‘𝐴) = (1 / (cos‘𝐴)))
40	39	oveq1d 7424	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((sec‘𝐴)↑2) = ((1 / (cos‘𝐴))↑2))
41		ax-1cn 11168	. . . . . 6 ⊢ 1 ∈ ℂ
42		expdiv 14079	. . . . . 6 ⊢ ((1 ∈ ℂ ∧ ((cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0) ∧ 2 ∈ ℕ₀) → ((1 / (cos‘𝐴))↑2) = ((1↑2) / ((cos‘𝐴)↑2)))
43	41, 13, 42	mp3an13 1453	. . . . 5 ⊢ (((cos‘𝐴) ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((1 / (cos‘𝐴))↑2) = ((1↑2) / ((cos‘𝐴)↑2)))
44	1, 43	sylan 581	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((1 / (cos‘𝐴))↑2) = ((1↑2) / ((cos‘𝐴)↑2)))
45		sq1 14159	. . . . 5 ⊢ (1↑2) = 1
46	45	oveq1i 7419	. . . 4 ⊢ ((1↑2) / ((cos‘𝐴)↑2)) = (1 / ((cos‘𝐴)↑2))
47	44, 46	eqtrdi 2789	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((1 / (cos‘𝐴))↑2) = (1 / ((cos‘𝐴)↑2)))
48	40, 47	eqtrd 2773	. 2 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → ((sec‘𝐴)↑2) = (1 / ((cos‘𝐴)↑2)))
49	38, 48	eqtr4d 2776	1 ⊢ ((𝐴 ∈ ℂ ∧ (cos‘𝐴) ≠ 0) → (1 + ((tan‘𝐴)↑2)) = ((sec‘𝐴)↑2))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 205 ∧ wa 397 = wceq 1542 ∈ wcel 2107 ≠ wne 2941 ‘cfv 6544 (class class class)co 7409 ℂcc 11108 0cc0 11110 1c1 11111 + caddc 11113 / cdiv 11871 2c2 12267 ℕ₀cn0 12472 ↑cexp 14027 sincsin 16007 cosccos 16008 tanctan 16009 seccsec 47786

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-10 2138 ax-11 2155 ax-12 2172 ax-ext 2704 ax-rep 5286 ax-sep 5300 ax-nul 5307 ax-pow 5364 ax-pr 5428 ax-un 7725 ax-inf2 9636 ax-cnex 11166 ax-resscn 11167 ax-1cn 11168 ax-icn 11169 ax-addcl 11170 ax-addrcl 11171 ax-mulcl 11172 ax-mulrcl 11173 ax-mulcom 11174 ax-addass 11175 ax-mulass 11176 ax-distr 11177 ax-i2m1 11178 ax-1ne0 11179 ax-1rid 11180 ax-rnegex 11181 ax-rrecex 11182 ax-cnre 11183 ax-pre-lttri 11184 ax-pre-lttrn 11185 ax-pre-ltadd 11186 ax-pre-mulgt0 11187 ax-pre-sup 11188

This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-nf 1787 df-sb 2069 df-mo 2535 df-eu 2564 df-clab 2711 df-cleq 2725 df-clel 2811 df-nfc 2886 df-ne 2942 df-nel 3048 df-ral 3063 df-rex 3072 df-rmo 3377 df-reu 3378 df-rab 3434 df-v 3477 df-sbc 3779 df-csb 3895 df-dif 3952 df-un 3954 df-in 3956 df-ss 3966 df-pss 3968 df-nul 4324 df-if 4530 df-pw 4605 df-sn 4630 df-pr 4632 df-op 4636 df-uni 4910 df-int 4952 df-iun 5000 df-br 5150 df-opab 5212 df-mpt 5233 df-tr 5267 df-id 5575 df-eprel 5581 df-po 5589 df-so 5590 df-fr 5632 df-se 5633 df-we 5634 df-xp 5683 df-rel 5684 df-cnv 5685 df-co 5686 df-dm 5687 df-rn 5688 df-res 5689 df-ima 5690 df-pred 6301 df-ord 6368 df-on 6369 df-lim 6370 df-suc 6371 df-iota 6496 df-fun 6546 df-fn 6547 df-f 6548 df-f1 6549 df-fo 6550 df-f1o 6551 df-fv 6552 df-isom 6553 df-riota 7365 df-ov 7412 df-oprab 7413 df-mpo 7414 df-om 7856 df-1st 7975 df-2nd 7976 df-frecs 8266 df-wrecs 8297 df-recs 8371 df-rdg 8410 df-1o 8466 df-er 8703 df-pm 8823 df-en 8940 df-dom 8941 df-sdom 8942 df-fin 8943 df-sup 9437 df-inf 9438 df-oi 9505 df-card 9934 df-pnf 11250 df-mnf 11251 df-xr 11252 df-ltxr 11253 df-le 11254 df-sub 11446 df-neg 11447 df-div 11872 df-nn 12213 df-2 12275 df-3 12276 df-n0 12473 df-z 12559 df-uz 12823 df-rp 12975 df-ico 13330 df-fz 13485 df-fzo 13628 df-fl 13757 df-seq 13967 df-exp 14028 df-fac 14234 df-bc 14263 df-hash 14291 df-shft 15014 df-cj 15046 df-re 15047 df-im 15048 df-sqrt 15182 df-abs 15183 df-limsup 15415 df-clim 15432 df-rlim 15433 df-sum 15633 df-ef 16011 df-sin 16013 df-cos 16014 df-tan 16015 df-sec 47789

This theorem is referenced by: (None)

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