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Theorem sqrlem2 14955

Description: Lemma for 01sqrex 14961. (Contributed by Mario Carneiro, 10-Jul-2013.)

**Hypotheses**
Ref	Expression
sqrlem1.1	⊢ 𝑆 = {𝑥 ∈ ℝ⁺ ∣ (𝑥↑2) ≤ 𝐴}
sqrlem1.2	⊢ 𝐵 = sup(𝑆, ℝ, < )

**Assertion**
Ref	Expression
sqrlem2	⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → 𝐴 ∈ 𝑆)

Distinct variable group: 𝑥,𝐴 Allowed substitution hints: 𝐵(𝑥) 𝑆(𝑥)

**Proof of Theorem sqrlem2**
Step	Hyp	Ref	Expression
1		simpl 483	. 2 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → 𝐴 ∈ ℝ⁺)
2		rpre 12738	. . . . 5 ⊢ (𝐴 ∈ ℝ⁺ → 𝐴 ∈ ℝ)
3		rpgt0 12742	. . . . 5 ⊢ (𝐴 ∈ ℝ⁺ → 0 < 𝐴)
4		1re 10975	. . . . . 6 ⊢ 1 ∈ ℝ
5		lemul1 11827	. . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 1 ∈ ℝ ∧ (𝐴 ∈ ℝ ∧ 0 < 𝐴)) → (𝐴 ≤ 1 ↔ (𝐴 · 𝐴) ≤ (1 · 𝐴)))
6	4, 5	mp3an2 1448	. . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ (𝐴 ∈ ℝ ∧ 0 < 𝐴)) → (𝐴 ≤ 1 ↔ (𝐴 · 𝐴) ≤ (1 · 𝐴)))
7	2, 2, 3, 6	syl12anc 834	. . . 4 ⊢ (𝐴 ∈ ℝ⁺ → (𝐴 ≤ 1 ↔ (𝐴 · 𝐴) ≤ (1 · 𝐴)))
8	7	biimpa 477	. . 3 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → (𝐴 · 𝐴) ≤ (1 · 𝐴))
9		rpcn 12740	. . . . 5 ⊢ (𝐴 ∈ ℝ⁺ → 𝐴 ∈ ℂ)
10	9	adantr 481	. . . 4 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → 𝐴 ∈ ℂ)
11		sqval 13835	. . . . 5 ⊢ (𝐴 ∈ ℂ → (𝐴↑2) = (𝐴 · 𝐴))
12	11	eqcomd 2744	. . . 4 ⊢ (𝐴 ∈ ℂ → (𝐴 · 𝐴) = (𝐴↑2))
13	10, 12	syl 17	. . 3 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → (𝐴 · 𝐴) = (𝐴↑2))
14	9	mulid2d 10993	. . . 4 ⊢ (𝐴 ∈ ℝ⁺ → (1 · 𝐴) = 𝐴)
15	14	adantr 481	. . 3 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → (1 · 𝐴) = 𝐴)
16	8, 13, 15	3brtr3d 5105	. 2 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → (𝐴↑2) ≤ 𝐴)
17		oveq1 7282	. . . 4 ⊢ (𝑥 = 𝐴 → (𝑥↑2) = (𝐴↑2))
18	17	breq1d 5084	. . 3 ⊢ (𝑥 = 𝐴 → ((𝑥↑2) ≤ 𝐴 ↔ (𝐴↑2) ≤ 𝐴))
19		sqrlem1.1	. . 3 ⊢ 𝑆 = {𝑥 ∈ ℝ⁺ ∣ (𝑥↑2) ≤ 𝐴}
20	18, 19	elrab2 3627	. 2 ⊢ (𝐴 ∈ 𝑆 ↔ (𝐴 ∈ ℝ⁺ ∧ (𝐴↑2) ≤ 𝐴))
21	1, 16, 20	sylanbrc 583	1 ⊢ ((𝐴 ∈ ℝ⁺ ∧ 𝐴 ≤ 1) → 𝐴 ∈ 𝑆)

Colors of variables: wff setvar class

Syntax hints: → wi 4 ↔ wb 205 ∧ wa 396 = wceq 1539 ∈ wcel 2106 {crab 3068 class class class wbr 5074 (class class class)co 7275 supcsup 9199 ℂcc 10869 ℝcr 10870 0cc0 10871 1c1 10872 · cmul 10876 < clt 11009 ≤ cle 11010 2c2 12028 ℝ⁺crp 12730 ↑cexp 13782

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 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-10 2137 ax-11 2154 ax-12 2171 ax-ext 2709 ax-sep 5223 ax-nul 5230 ax-pow 5288 ax-pr 5352 ax-un 7588 ax-cnex 10927 ax-resscn 10928 ax-1cn 10929 ax-icn 10930 ax-addcl 10931 ax-addrcl 10932 ax-mulcl 10933 ax-mulrcl 10934 ax-mulcom 10935 ax-addass 10936 ax-mulass 10937 ax-distr 10938 ax-i2m1 10939 ax-1ne0 10940 ax-1rid 10941 ax-rnegex 10942 ax-rrecex 10943 ax-cnre 10944 ax-pre-lttri 10945 ax-pre-lttrn 10946 ax-pre-ltadd 10947 ax-pre-mulgt0 10948

This theorem depends on definitions: df-bi 206 df-an 397 df-or 845 df-3or 1087 df-3an 1088 df-tru 1542 df-fal 1552 df-ex 1783 df-nf 1787 df-sb 2068 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2816 df-nfc 2889 df-ne 2944 df-nel 3050 df-ral 3069 df-rex 3070 df-reu 3072 df-rab 3073 df-v 3434 df-sbc 3717 df-csb 3833 df-dif 3890 df-un 3892 df-in 3894 df-ss 3904 df-pss 3906 df-nul 4257 df-if 4460 df-pw 4535 df-sn 4562 df-pr 4564 df-op 4568 df-uni 4840 df-iun 4926 df-br 5075 df-opab 5137 df-mpt 5158 df-tr 5192 df-id 5489 df-eprel 5495 df-po 5503 df-so 5504 df-fr 5544 df-we 5546 df-xp 5595 df-rel 5596 df-cnv 5597 df-co 5598 df-dm 5599 df-rn 5600 df-res 5601 df-ima 5602 df-pred 6202 df-ord 6269 df-on 6270 df-lim 6271 df-suc 6272 df-iota 6391 df-fun 6435 df-fn 6436 df-f 6437 df-f1 6438 df-fo 6439 df-f1o 6440 df-fv 6441 df-riota 7232 df-ov 7278 df-oprab 7279 df-mpo 7280 df-om 7713 df-2nd 7832 df-frecs 8097 df-wrecs 8128 df-recs 8202 df-rdg 8241 df-er 8498 df-en 8734 df-dom 8735 df-sdom 8736 df-pnf 11011 df-mnf 11012 df-xr 11013 df-ltxr 11014 df-le 11015 df-sub 11207 df-neg 11208 df-nn 11974 df-2 12036 df-n0 12234 df-z 12320 df-uz 12583 df-rp 12731 df-seq 13722 df-exp 13783

This theorem is referenced by: sqrlem3 14956 sqrlem4 14957

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