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Mirrors > Home > ILE Home > Th. List > sqrtgt0 | GIF version |
Description: The square root function is positive for positive input. (Contributed by Mario Carneiro, 10-Jul-2013.) (Revised by Mario Carneiro, 6-Sep-2013.) |
Ref | Expression |
---|---|
sqrtgt0 | ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 < (√‘𝐴)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr 109 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 < 𝐴) | |
2 | sq0 10106 | . . . 4 ⊢ (0↑2) = 0 | |
3 | 2 | a1i 9 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (0↑2) = 0) |
4 | 0red 7550 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 ∈ ℝ) | |
5 | simpl 108 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 𝐴 ∈ ℝ) | |
6 | 4, 5, 1 | ltled 7663 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 ≤ 𝐴) |
7 | resqrtth 10525 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 ≤ 𝐴) → ((√‘𝐴)↑2) = 𝐴) | |
8 | 6, 7 | syldan 277 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ((√‘𝐴)↑2) = 𝐴) |
9 | 1, 3, 8 | 3brtr4d 3881 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (0↑2) < ((√‘𝐴)↑2)) |
10 | resqrtcl 10523 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 ≤ 𝐴) → (√‘𝐴) ∈ ℝ) | |
11 | 6, 10 | syldan 277 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (√‘𝐴) ∈ ℝ) |
12 | 4 | leidd 8053 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 ≤ 0) |
13 | sqrtge0 10527 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 ≤ 𝐴) → 0 ≤ (√‘𝐴)) | |
14 | 6, 13 | syldan 277 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 ≤ (√‘𝐴)) |
15 | 4, 11, 12, 14 | lt2sqd 10178 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (0 < (√‘𝐴) ↔ (0↑2) < ((√‘𝐴)↑2))) |
16 | 9, 15 | mpbird 166 | 1 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 < (√‘𝐴)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 = wceq 1290 ∈ wcel 1439 class class class wbr 3851 ‘cfv 5028 (class class class)co 5666 ℝcr 7410 0cc0 7411 < clt 7583 ≤ cle 7584 2c2 8534 ↑cexp 10015 √csqrt 10490 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 580 ax-in2 581 ax-io 666 ax-5 1382 ax-7 1383 ax-gen 1384 ax-ie1 1428 ax-ie2 1429 ax-8 1441 ax-10 1442 ax-11 1443 ax-i12 1444 ax-bndl 1445 ax-4 1446 ax-13 1450 ax-14 1451 ax-17 1465 ax-i9 1469 ax-ial 1473 ax-i5r 1474 ax-ext 2071 ax-coll 3960 ax-sep 3963 ax-nul 3971 ax-pow 4015 ax-pr 4045 ax-un 4269 ax-setind 4366 ax-iinf 4416 ax-cnex 7497 ax-resscn 7498 ax-1cn 7499 ax-1re 7500 ax-icn 7501 ax-addcl 7502 ax-addrcl 7503 ax-mulcl 7504 ax-mulrcl 7505 ax-addcom 7506 ax-mulcom 7507 ax-addass 7508 ax-mulass 7509 ax-distr 7510 ax-i2m1 7511 ax-0lt1 7512 ax-1rid 7513 ax-0id 7514 ax-rnegex 7515 ax-precex 7516 ax-cnre 7517 ax-pre-ltirr 7518 ax-pre-ltwlin 7519 ax-pre-lttrn 7520 ax-pre-apti 7521 ax-pre-ltadd 7522 ax-pre-mulgt0 7523 ax-pre-mulext 7524 ax-arch 7525 ax-caucvg 7526 |
This theorem depends on definitions: df-bi 116 df-dc 782 df-3or 926 df-3an 927 df-tru 1293 df-fal 1296 df-nf 1396 df-sb 1694 df-eu 1952 df-mo 1953 df-clab 2076 df-cleq 2082 df-clel 2085 df-nfc 2218 df-ne 2257 df-nel 2352 df-ral 2365 df-rex 2366 df-reu 2367 df-rmo 2368 df-rab 2369 df-v 2622 df-sbc 2842 df-csb 2935 df-dif 3002 df-un 3004 df-in 3006 df-ss 3013 df-nul 3288 df-if 3398 df-pw 3435 df-sn 3456 df-pr 3457 df-op 3459 df-uni 3660 df-int 3695 df-iun 3738 df-br 3852 df-opab 3906 df-mpt 3907 df-tr 3943 df-id 4129 df-po 4132 df-iso 4133 df-iord 4202 df-on 4204 df-ilim 4205 df-suc 4207 df-iom 4419 df-xp 4458 df-rel 4459 df-cnv 4460 df-co 4461 df-dm 4462 df-rn 4463 df-res 4464 df-ima 4465 df-iota 4993 df-fun 5030 df-fn 5031 df-f 5032 df-f1 5033 df-fo 5034 df-f1o 5035 df-fv 5036 df-riota 5622 df-ov 5669 df-oprab 5670 df-mpt2 5671 df-1st 5925 df-2nd 5926 df-recs 6084 df-frec 6170 df-pnf 7585 df-mnf 7586 df-xr 7587 df-ltxr 7588 df-le 7589 df-sub 7716 df-neg 7717 df-reap 8113 df-ap 8120 df-div 8201 df-inn 8484 df-2 8542 df-3 8543 df-4 8544 df-n0 8735 df-z 8812 df-uz 9081 df-rp 9196 df-iseq 9914 df-seq3 9915 df-exp 10016 df-rsqrt 10492 |
This theorem is referenced by: rpsqrtcl 10535 sqrtgt0i 10615 |
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