tanabsge - Metamath Proof Explorer

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Theorem tanabsge 26633

Description: The tangent function is greater than or equal to its argument in absolute value. (Contributed by Mario Carneiro, 25-Feb-2015.)

**Assertion**
Ref	Expression
tanabsge	⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (abs‘𝐴) ≤ (abs‘(tan‘𝐴)))

**Proof of Theorem tanabsge**
Step	Hyp	Ref	Expression
1		elioore 13398	. . . . . 6 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → 𝐴 ∈ ℝ)
2	1	adantr 485	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 𝐴 ∈ ℝ)
3	2	renegcld 11637	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 ∈ ℝ)
4	1	lt0neg1d 11779	. . . . . . . . . 10 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (𝐴 < 0 ↔ 0 < -𝐴))
5	4	biimpa 481	. . . . . . . . 9 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 0 < -𝐴)
6		eliooord 13428	. . . . . . . . . . . 12 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (-(π / 2) < 𝐴 ∧ 𝐴 < (π / 2)))
7	6	simpld 499	. . . . . . . . . . 11 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → -(π / 2) < 𝐴)
8	7	adantr 485	. . . . . . . . . 10 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -(π / 2) < 𝐴)
9		halfpire 26591	. . . . . . . . . . 11 ⊢ (π / 2) ∈ ℝ
10		ltnegcon1 11711	. . . . . . . . . . 11 ⊢ (((π / 2) ∈ ℝ ∧ 𝐴 ∈ ℝ) → (-(π / 2) < 𝐴 ↔ -𝐴 < (π / 2)))
11	9, 2, 10	sylancr 598	. . . . . . . . . 10 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (-(π / 2) < 𝐴 ↔ -𝐴 < (π / 2)))
12	8, 11	mpbid 235	. . . . . . . . 9 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 < (π / 2))
13		0xr 11252	. . . . . . . . . 10 ⊢ 0 ∈ ℝ^*
14	9	rexri 11263	. . . . . . . . . 10 ⊢ (π / 2) ∈ ℝ^*
15		elioo2 13409	. . . . . . . . . 10 ⊢ ((0 ∈ ℝ^* ∧ (π / 2) ∈ ℝ^*) → (-𝐴 ∈ (0(,)(π / 2)) ↔ (-𝐴 ∈ ℝ ∧ 0 < -𝐴 ∧ -𝐴 < (π / 2))))
16	13, 14, 15	mp2an 704	. . . . . . . . 9 ⊢ (-𝐴 ∈ (0(,)(π / 2)) ↔ (-𝐴 ∈ ℝ ∧ 0 < -𝐴 ∧ -𝐴 < (π / 2)))
17	3, 5, 12, 16	syl3anbrc 1360	. . . . . . . 8 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 ∈ (0(,)(π / 2)))
18		sincosq1sgn 26625	. . . . . . . 8 ⊢ (-𝐴 ∈ (0(,)(π / 2)) → (0 < (sin‘-𝐴) ∧ 0 < (cos‘-𝐴)))
19	17, 18	syl 18	. . . . . . 7 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (0 < (sin‘-𝐴) ∧ 0 < (cos‘-𝐴)))
20	19	simprd 500	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 0 < (cos‘-𝐴))
21	20	gt0ne0d 11774	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (cos‘-𝐴) ≠ 0)
22	3, 21	retancld 16197	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (tan‘-𝐴) ∈ ℝ)
23		tangtx 26632	. . . . 5 ⊢ (-𝐴 ∈ (0(,)(π / 2)) → -𝐴 < (tan‘-𝐴))
24	17, 23	syl 18	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 < (tan‘-𝐴))
25	3, 22, 24	ltled 11354	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 ≤ (tan‘-𝐴))
26		0re 11206	. . . . . 6 ⊢ 0 ∈ ℝ
27		ltle 11294	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 0 ∈ ℝ) → (𝐴 < 0 → 𝐴 ≤ 0))
28	1, 26, 27	sylancl 597	. . . . 5 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (𝐴 < 0 → 𝐴 ≤ 0))
29	28	imp 411	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 𝐴 ≤ 0)
30	2, 29	absnidd 15461	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘𝐴) = -𝐴)
31	1	recnd 11233	. . . . . . . . 9 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → 𝐴 ∈ ℂ)
32	31	adantr 485	. . . . . . . 8 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 𝐴 ∈ ℂ)
33	32	negnegd 11556	. . . . . . 7 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → --𝐴 = 𝐴)
34	33	fveq2d 6883	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (tan‘--𝐴) = (tan‘𝐴))
35	32	negcld 11552	. . . . . . 7 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → -𝐴 ∈ ℂ)
36		tanneg 16200	. . . . . . 7 ⊢ ((-𝐴 ∈ ℂ ∧ (cos‘-𝐴) ≠ 0) → (tan‘--𝐴) = -(tan‘-𝐴))
37	35, 21, 36	syl2anc 595	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (tan‘--𝐴) = -(tan‘-𝐴))
38	34, 37	eqtr3d 2806	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (tan‘𝐴) = -(tan‘-𝐴))
39	38	fveq2d 6883	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘(tan‘𝐴)) = (abs‘-(tan‘-𝐴)))
40	22	recnd 11233	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (tan‘-𝐴) ∈ ℂ)
41	40	absnegd 15499	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘-(tan‘-𝐴)) = (abs‘(tan‘-𝐴)))
42		0red 11207	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 0 ∈ ℝ)
43		ltle 11294	. . . . . . . 8 ⊢ ((0 ∈ ℝ ∧ -𝐴 ∈ ℝ) → (0 < -𝐴 → 0 ≤ -𝐴))
44	26, 3, 43	sylancr 598	. . . . . . 7 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (0 < -𝐴 → 0 ≤ -𝐴))
45	5, 44	mpd 16	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 0 ≤ -𝐴)
46	42, 3, 22, 45, 25	letrd 11363	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → 0 ≤ (tan‘-𝐴))
47	22, 46	absidd 15470	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘(tan‘-𝐴)) = (tan‘-𝐴))
48	39, 41, 47	3eqtrd 2808	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘(tan‘𝐴)) = (tan‘-𝐴))
49	25, 30, 48	3brtr4d 5144	. 2 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 < 0) → (abs‘𝐴) ≤ (abs‘(tan‘𝐴)))
50		abs0 15332	. . . . . 6 ⊢ (abs‘0) = 0
51	50, 26	eqeltri 2865	. . . . 5 ⊢ (abs‘0) ∈ ℝ
52	51	leidi 11744	. . . 4 ⊢ (abs‘0) ≤ (abs‘0)
53	52	a1i 11	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (abs‘0) ≤ (abs‘0))
54		simpr 489	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → 𝐴 = 0)
55	54	fveq2d 6883	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (abs‘𝐴) = (abs‘0))
56	54	fveq2d 6883	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (tan‘𝐴) = (tan‘0))
57		tan0 16203	. . . . 5 ⊢ (tan‘0) = 0
58	56, 57	eqtrdi 2820	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (tan‘𝐴) = 0)
59	58	fveq2d 6883	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (abs‘(tan‘𝐴)) = (abs‘0))
60	53, 55, 59	3brtr4d 5144	. 2 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 𝐴 = 0) → (abs‘𝐴) ≤ (abs‘(tan‘𝐴)))
61	1	adantr 485	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 𝐴 ∈ ℝ)
62		simpr 489	. . . . . . . . 9 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 0 < 𝐴)
63	6	simprd 500	. . . . . . . . . 10 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → 𝐴 < (π / 2))
64	63	adantr 485	. . . . . . . . 9 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 𝐴 < (π / 2))
65		elioo2 13409	. . . . . . . . . 10 ⊢ ((0 ∈ ℝ^* ∧ (π / 2) ∈ ℝ^*) → (𝐴 ∈ (0(,)(π / 2)) ↔ (𝐴 ∈ ℝ ∧ 0 < 𝐴 ∧ 𝐴 < (π / 2))))
66	13, 14, 65	mp2an 704	. . . . . . . . 9 ⊢ (𝐴 ∈ (0(,)(π / 2)) ↔ (𝐴 ∈ ℝ ∧ 0 < 𝐴 ∧ 𝐴 < (π / 2)))
67	61, 62, 64, 66	syl3anbrc 1360	. . . . . . . 8 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 𝐴 ∈ (0(,)(π / 2)))
68		sincosq1sgn 26625	. . . . . . . 8 ⊢ (𝐴 ∈ (0(,)(π / 2)) → (0 < (sin‘𝐴) ∧ 0 < (cos‘𝐴)))
69	67, 68	syl 18	. . . . . . 7 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (0 < (sin‘𝐴) ∧ 0 < (cos‘𝐴)))
70	69	simprd 500	. . . . . 6 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 0 < (cos‘𝐴))
71	70	gt0ne0d 11774	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (cos‘𝐴) ≠ 0)
72	61, 71	retancld 16197	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (tan‘𝐴) ∈ ℝ)
73		tangtx 26632	. . . . 5 ⊢ (𝐴 ∈ (0(,)(π / 2)) → 𝐴 < (tan‘𝐴))
74	67, 73	syl 18	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 𝐴 < (tan‘𝐴))
75	61, 72, 74	ltled 11354	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 𝐴 ≤ (tan‘𝐴))
76		ltle 11294	. . . . . 6 ⊢ ((0 ∈ ℝ ∧ 𝐴 ∈ ℝ) → (0 < 𝐴 → 0 ≤ 𝐴))
77	26, 1, 76	sylancr 598	. . . . 5 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (0 < 𝐴 → 0 ≤ 𝐴))
78	77	imp 411	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 0 ≤ 𝐴)
79	61, 78	absidd 15470	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (abs‘𝐴) = 𝐴)
80		0red 11207	. . . . 5 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 0 ∈ ℝ)
81	80, 61, 72, 78, 75	letrd 11363	. . . 4 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → 0 ≤ (tan‘𝐴))
82	72, 81	absidd 15470	. . 3 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (abs‘(tan‘𝐴)) = (tan‘𝐴))
83	75, 79, 82	3brtr4d 5144	. 2 ⊢ ((𝐴 ∈ (-(π / 2)(,)(π / 2)) ∧ 0 < 𝐴) → (abs‘𝐴) ≤ (abs‘(tan‘𝐴)))
84		lttri4 11290	. . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 ∈ ℝ) → (𝐴 < 0 ∨ 𝐴 = 0 ∨ 0 < 𝐴))
85	1, 26, 84	sylancl 597	. 2 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (𝐴 < 0 ∨ 𝐴 = 0 ∨ 0 < 𝐴))
86	49, 60, 83, 85	mpjao3dan 1457	1 ⊢ (𝐴 ∈ (-(π / 2)(,)(π / 2)) → (abs‘𝐴) ≤ (abs‘(tan‘𝐴)))

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 209 ∧ wa 400 ∨ w3o 1100 ∧ w3a 1101 = wceq 1567 ∈ wcel 2149 ≠ wne 2964 class class class wbr 5110 ‘cfv 6534 (class class class)co 7408 ℂcc 11094 ℝcr 11095 0cc0 11096 ℝ^*cxr 11238 < clt 11239 ≤ cle 11240 -cneg 11438 / cdiv 11867 2c2 12291 (,)cioo 13368 abscabs 15281 sincsin 16113 cosccos 16114 tanctan 16115 πcpi 16116

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1822 ax-4 1836 ax-5 1937 ax-6 1994 ax-7 2035 ax-8 2151 ax-9 2159 ax-10 2182 ax-11 2198 ax-12 2219 ax-ext 2741 ax-rep 5239 ax-sep 5258 ax-nul 5268 ax-pow 5334 ax-pr 5402 ax-un 7730 ax-inf2 9606 ax-cnex 11152 ax-resscn 11153 ax-1cn 11154 ax-icn 11155 ax-addcl 11156 ax-addrcl 11157 ax-mulcl 11158 ax-mulrcl 11159 ax-mulcom 11160 ax-addass 11161 ax-mulass 11162 ax-distr 11163 ax-i2m1 11164 ax-1ne0 11165 ax-1rid 11166 ax-rnegex 11167 ax-rrecex 11168 ax-cnre 11169 ax-pre-lttri 11170 ax-pre-lttrn 11171 ax-pre-ltadd 11172 ax-pre-mulgt0 11173 ax-pre-sup 11174 ax-addf 11175

This theorem depends on definitions: df-bi 210 df-an 401 df-or 861 df-3or 1102 df-3an 1103 df-tru 1570 df-fal 1580 df-ex 1807 df-nf 1811 df-sb 2098 df-mo 2573 df-eu 2603 df-clab 2748 df-cleq 2761 df-clel 2844 df-nfc 2918 df-ne 2965 df-nel 3071 df-ral 3086 df-rex 3096 df-rmo 3376 df-reu 3377 df-rab 3424 df-v 3465 df-sbc 3754 df-csb 3862 df-dif 3916 df-un 3918 df-in 3920 df-ss 3930 df-pss 3933 df-nul 4295 df-if 4490 df-pw 4566 df-sn 4592 df-pr 4594 df-tp 4596 df-op 4598 df-uni 4874 df-int 4914 df-iun 4959 df-iin 4960 df-br 5111 df-opab 5175 df-mpt 5194 df-tr 5220 df-id 5554 df-eprel 5559 df-po 5567 df-so 5568 df-fr 5612 df-se 5613 df-we 5614 df-xp 5665 df-rel 5666 df-cnv 5667 df-co 5668 df-dm 5669 df-rn 5670 df-res 5671 df-ima 5672 df-pred 6300 df-ord 6361 df-on 6362 df-lim 6363 df-suc 6364 df-iota 6490 df-fun 6536 df-fn 6537 df-f 6538 df-f1 6539 df-fo 6540 df-f1o 6541 df-fv 6542 df-isom 6543 df-riota 7365 df-ov 7411 df-oprab 7412 df-mpo 7413 df-of 7672 df-om 7859 df-1st 7982 df-2nd 7983 df-supp 8153 df-frecs 8274 df-wrecs 8305 df-recs 8354 df-rdg 8393 df-1o 8449 df-2o 8450 df-er 8690 df-map 8822 df-pm 8823 df-ixp 8892 df-en 8940 df-dom 8941 df-sdom 8942 df-fin 8943 df-fsupp 9318 df-fi 9367 df-sup 9398 df-inf 9399 df-oi 9468 df-card 9921 df-pnf 11241 df-mnf 11242 df-xr 11243 df-ltxr 11244 df-le 11245 df-sub 11439 df-neg 11440 df-div 11868 df-nn 12230 df-2 12299 df-3 12300 df-4 12301 df-5 12302 df-6 12303 df-7 12304 df-8 12305 df-9 12306 df-n0 12501 df-z 12588 df-dec 12708 df-uz 12859 df-q 12969 df-rp 13013 df-xneg 13133 df-xadd 13134 df-xmul 13135 df-ioo 13372 df-ioc 13373 df-ico 13374 df-icc 13375 df-fz 13532 df-fzo 13679 df-fl 13821 df-seq 14034 df-exp 14094 df-fac 14306 df-bc 14335 df-hash 14363 df-shft 15100 df-cj 15146 df-re 15147 df-im 15148 df-sqrt 15282 df-abs 15283 df-limsup 15518 df-clim 15535 df-rlim 15536 df-sum 15734 df-ef 16117 df-sin 16119 df-cos 16120 df-tan 16121 df-pi 16122 df-struct 17203 df-sets 17220 df-slot 17238 df-ndx 17250 df-base 17266 df-ress 17287 df-plusg 17319 df-mulr 17320 df-starv 17321 df-sca 17322 df-vsca 17323 df-ip 17324 df-tset 17325 df-ple 17326 df-ds 17328 df-unif 17329 df-hom 17330 df-cco 17331 df-rest 17471 df-topn 17472 df-0g 17490 df-gsum 17491 df-topgen 17492 df-pt 17493 df-prds 17496 df-xrs 17552 df-qtop 17557 df-imas 17558 df-xps 17560 df-mre 17634 df-mrc 17635 df-acs 17637 df-mgm 18694 df-sgrp 18773 df-mnd 18789 df-submnd 18838 df-mulg 19130 df-cntz 19383 df-cmn 19848 df-psmet 21479 df-xmet 21480 df-met 21481 df-bl 21482 df-mopn 21483 df-fbas 21484 df-fg 21485 df-cnfld 21488 df-top 23016 df-topon 23033 df-topsp 23055 df-bases 23068 df-cld 23141 df-ntr 23142 df-cls 23143 df-nei 23220 df-lp 23258 df-perf 23259 df-cn 23349 df-cnp 23350 df-haus 23437 df-tx 23684 df-hmeo 23877 df-fil 23968 df-fm 24060 df-flim 24061 df-flf 24062 df-xms 24442 df-ms 24443 df-tms 24444 df-cncf 25002 df-limc 25990 df-dv 25991

This theorem is referenced by: logcnlem4 26772

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