logcnlem2 - Metamath Proof Explorer

	Metamath Proof Explorer		< Previous Next > Nearby theorems
Mirrors > Home > MPE Home > Th. List > logcnlem2		Structured version Visualization version GIF version

Theorem logcnlem2 26570

Description: Lemma for logcn 26574. (Contributed by Mario Carneiro, 25-Feb-2015.)

**Hypotheses**
Ref	Expression
logcn.d	⊢ 𝐷 = (ℂ ∖ (-∞(,]0))
logcnlem.s	⊢ 𝑆 = if(𝐴 ∈ ℝ⁺, 𝐴, (abs‘(ℑ‘𝐴)))
logcnlem.t	⊢ 𝑇 = ((abs‘𝐴) · (𝑅 / (1 + 𝑅)))
logcnlem.a	⊢ (𝜑 → 𝐴 ∈ 𝐷)
logcnlem.r	⊢ (𝜑 → 𝑅 ∈ ℝ⁺)

**Assertion**
Ref	Expression
logcnlem2	⊢ (𝜑 → if(𝑆 ≤ 𝑇, 𝑆, 𝑇) ∈ ℝ⁺)

**Proof of Theorem logcnlem2**
Step	Hyp	Ref	Expression
1		logcnlem.s	. . 3 ⊢ 𝑆 = if(𝐴 ∈ ℝ⁺, 𝐴, (abs‘(ℑ‘𝐴)))
2		simpr 484	. . . 4 ⊢ ((𝜑 ∧ 𝐴 ∈ ℝ⁺) → 𝐴 ∈ ℝ⁺)
3		logcnlem.a	. . . . . . . . 9 ⊢ (𝜑 → 𝐴 ∈ 𝐷)
4		logcn.d	. . . . . . . . . . 11 ⊢ 𝐷 = (ℂ ∖ (-∞(,]0))
5	4	ellogdm 26566	. . . . . . . . . 10 ⊢ (𝐴 ∈ 𝐷 ↔ (𝐴 ∈ ℂ ∧ (𝐴 ∈ ℝ → 𝐴 ∈ ℝ⁺)))
6	5	simplbi 497	. . . . . . . . 9 ⊢ (𝐴 ∈ 𝐷 → 𝐴 ∈ ℂ)
7	3, 6	syl 17	. . . . . . . 8 ⊢ (𝜑 → 𝐴 ∈ ℂ)
8	7	imcld 15168	. . . . . . 7 ⊢ (𝜑 → (ℑ‘𝐴) ∈ ℝ)
9	8	adantr 480	. . . . . 6 ⊢ ((𝜑 ∧ ¬ 𝐴 ∈ ℝ⁺) → (ℑ‘𝐴) ∈ ℝ)
10	9	recnd 11266	. . . . 5 ⊢ ((𝜑 ∧ ¬ 𝐴 ∈ ℝ⁺) → (ℑ‘𝐴) ∈ ℂ)
11		reim0b 15092	. . . . . . . . 9 ⊢ (𝐴 ∈ ℂ → (𝐴 ∈ ℝ ↔ (ℑ‘𝐴) = 0))
12	7, 11	syl 17	. . . . . . . 8 ⊢ (𝜑 → (𝐴 ∈ ℝ ↔ (ℑ‘𝐴) = 0))
13	5	simprbi 496	. . . . . . . . 9 ⊢ (𝐴 ∈ 𝐷 → (𝐴 ∈ ℝ → 𝐴 ∈ ℝ⁺))
14	3, 13	syl 17	. . . . . . . 8 ⊢ (𝜑 → (𝐴 ∈ ℝ → 𝐴 ∈ ℝ⁺))
15	12, 14	sylbird 260	. . . . . . 7 ⊢ (𝜑 → ((ℑ‘𝐴) = 0 → 𝐴 ∈ ℝ⁺))
16	15	necon3bd 2950	. . . . . 6 ⊢ (𝜑 → (¬ 𝐴 ∈ ℝ⁺ → (ℑ‘𝐴) ≠ 0))
17	16	imp 406	. . . . 5 ⊢ ((𝜑 ∧ ¬ 𝐴 ∈ ℝ⁺) → (ℑ‘𝐴) ≠ 0)
18	10, 17	absrpcld 15421	. . . 4 ⊢ ((𝜑 ∧ ¬ 𝐴 ∈ ℝ⁺) → (abs‘(ℑ‘𝐴)) ∈ ℝ⁺)
19	2, 18	ifclda 4559	. . 3 ⊢ (𝜑 → if(𝐴 ∈ ℝ⁺, 𝐴, (abs‘(ℑ‘𝐴))) ∈ ℝ⁺)
20	1, 19	eqeltrid 2833	. 2 ⊢ (𝜑 → 𝑆 ∈ ℝ⁺)
21		logcnlem.t	. . 3 ⊢ 𝑇 = ((abs‘𝐴) · (𝑅 / (1 + 𝑅)))
22	4	logdmn0 26567	. . . . . 6 ⊢ (𝐴 ∈ 𝐷 → 𝐴 ≠ 0)
23	3, 22	syl 17	. . . . 5 ⊢ (𝜑 → 𝐴 ≠ 0)
24	7, 23	absrpcld 15421	. . . 4 ⊢ (𝜑 → (abs‘𝐴) ∈ ℝ⁺)
25		logcnlem.r	. . . . 5 ⊢ (𝜑 → 𝑅 ∈ ℝ⁺)
26		1rp 13004	. . . . . 6 ⊢ 1 ∈ ℝ⁺
27		rpaddcl 13022	. . . . . 6 ⊢ ((1 ∈ ℝ⁺ ∧ 𝑅 ∈ ℝ⁺) → (1 + 𝑅) ∈ ℝ⁺)
28	26, 25, 27	sylancr 586	. . . . 5 ⊢ (𝜑 → (1 + 𝑅) ∈ ℝ⁺)
29	25, 28	rpdivcld 13059	. . . 4 ⊢ (𝜑 → (𝑅 / (1 + 𝑅)) ∈ ℝ⁺)
30	24, 29	rpmulcld 13058	. . 3 ⊢ (𝜑 → ((abs‘𝐴) · (𝑅 / (1 + 𝑅))) ∈ ℝ⁺)
31	21, 30	eqeltrid 2833	. 2 ⊢ (𝜑 → 𝑇 ∈ ℝ⁺)
32	20, 31	ifcld 4570	1 ⊢ (𝜑 → if(𝑆 ≤ 𝑇, 𝑆, 𝑇) ∈ ℝ⁺)

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ wa 395 = wceq 1534 ∈ wcel 2099 ≠ wne 2936 ∖ cdif 3942 ifcif 4524 class class class wbr 5142 ‘cfv 6542 (class class class)co 7414 ℂcc 11130 ℝcr 11131 0cc0 11132 1c1 11133 + caddc 11135 · cmul 11137 -∞cmnf 11270 ≤ cle 11273 / cdiv 11895 ℝ⁺crp 13000 (,]cioc 13351 ℑcim 15071 abscabs 15207

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1790 ax-4 1804 ax-5 1906 ax-6 1964 ax-7 2004 ax-8 2101 ax-9 2109 ax-10 2130 ax-11 2147 ax-12 2167 ax-ext 2699 ax-sep 5293 ax-nul 5300 ax-pow 5359 ax-pr 5423 ax-un 7734 ax-cnex 11188 ax-resscn 11189 ax-1cn 11190 ax-icn 11191 ax-addcl 11192 ax-addrcl 11193 ax-mulcl 11194 ax-mulrcl 11195 ax-mulcom 11196 ax-addass 11197 ax-mulass 11198 ax-distr 11199 ax-i2m1 11200 ax-1ne0 11201 ax-1rid 11202 ax-rnegex 11203 ax-rrecex 11204 ax-cnre 11205 ax-pre-lttri 11206 ax-pre-lttrn 11207 ax-pre-ltadd 11208 ax-pre-mulgt0 11209 ax-pre-sup 11210

This theorem depends on definitions: df-bi 206 df-an 396 df-or 847 df-3or 1086 df-3an 1087 df-tru 1537 df-fal 1547 df-ex 1775 df-nf 1779 df-sb 2061 df-mo 2530 df-eu 2559 df-clab 2706 df-cleq 2720 df-clel 2806 df-nfc 2881 df-ne 2937 df-nel 3043 df-ral 3058 df-rex 3067 df-rmo 3372 df-reu 3373 df-rab 3429 df-v 3472 df-sbc 3776 df-csb 3891 df-dif 3948 df-un 3950 df-in 3952 df-ss 3962 df-pss 3964 df-nul 4319 df-if 4525 df-pw 4600 df-sn 4625 df-pr 4627 df-op 4631 df-uni 4904 df-iun 4993 df-br 5143 df-opab 5205 df-mpt 5226 df-tr 5260 df-id 5570 df-eprel 5576 df-po 5584 df-so 5585 df-fr 5627 df-we 5629 df-xp 5678 df-rel 5679 df-cnv 5680 df-co 5681 df-dm 5682 df-rn 5683 df-res 5684 df-ima 5685 df-pred 6299 df-ord 6366 df-on 6367 df-lim 6368 df-suc 6369 df-iota 6494 df-fun 6544 df-fn 6545 df-f 6546 df-f1 6547 df-fo 6548 df-f1o 6549 df-fv 6550 df-riota 7370 df-ov 7417 df-oprab 7418 df-mpo 7419 df-om 7865 df-2nd 7988 df-frecs 8280 df-wrecs 8311 df-recs 8385 df-rdg 8424 df-er 8718 df-en 8958 df-dom 8959 df-sdom 8960 df-sup 9459 df-pnf 11274 df-mnf 11275 df-xr 11276 df-ltxr 11277 df-le 11278 df-sub 11470 df-neg 11471 df-div 11896 df-nn 12237 df-2 12299 df-3 12300 df-n0 12497 df-z 12583 df-uz 12847 df-rp 13001 df-ioc 13355 df-seq 13993 df-exp 14053 df-cj 15072 df-re 15073 df-im 15074 df-sqrt 15208 df-abs 15209

This theorem is referenced by: logcnlem5 26573

W3C validator

	
		OSZAR »