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Mirrors > Home > MPE Home > Th. List > zsqrtelqelz | Structured version Visualization version GIF version |
Description: If an integer has a rational square root, that root is must be an integer. (Contributed by Stefan O'Rear, 15-Sep-2014.) |
Ref | Expression |
---|---|
zsqrtelqelz | ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (√‘𝐴) ∈ ℤ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | qdencl 15915 | . . . . 5 ⊢ ((√‘𝐴) ∈ ℚ → (denom‘(√‘𝐴)) ∈ ℕ) | |
2 | 1 | adantl 482 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘(√‘𝐴)) ∈ ℕ) |
3 | 2 | nnred 11506 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘(√‘𝐴)) ∈ ℝ) |
4 | 1red 10493 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → 1 ∈ ℝ) | |
5 | 2 | nnnn0d 11808 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘(√‘𝐴)) ∈ ℕ0) |
6 | 5 | nn0ge0d 11811 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → 0 ≤ (denom‘(√‘𝐴))) |
7 | 0le1 11016 | . . . 4 ⊢ 0 ≤ 1 | |
8 | 7 | a1i 11 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → 0 ≤ 1) |
9 | sq1 13413 | . . . . 5 ⊢ (1↑2) = 1 | |
10 | 9 | a1i 11 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (1↑2) = 1) |
11 | zcn 11839 | . . . . . . . 8 ⊢ (𝐴 ∈ ℤ → 𝐴 ∈ ℂ) | |
12 | 11 | sqsqrtd 14638 | . . . . . . 7 ⊢ (𝐴 ∈ ℤ → ((√‘𝐴)↑2) = 𝐴) |
13 | 12 | adantr 481 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → ((√‘𝐴)↑2) = 𝐴) |
14 | 13 | fveq2d 6547 | . . . . 5 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘((√‘𝐴)↑2)) = (denom‘𝐴)) |
15 | simpl 483 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → 𝐴 ∈ ℤ) | |
16 | zq 12208 | . . . . . . . 8 ⊢ (𝐴 ∈ ℤ → 𝐴 ∈ ℚ) | |
17 | 16 | adantr 481 | . . . . . . 7 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → 𝐴 ∈ ℚ) |
18 | qden1elz 15931 | . . . . . . 7 ⊢ (𝐴 ∈ ℚ → ((denom‘𝐴) = 1 ↔ 𝐴 ∈ ℤ)) | |
19 | 17, 18 | syl 17 | . . . . . 6 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → ((denom‘𝐴) = 1 ↔ 𝐴 ∈ ℤ)) |
20 | 15, 19 | mpbird 258 | . . . . 5 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘𝐴) = 1) |
21 | 14, 20 | eqtrd 2831 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘((√‘𝐴)↑2)) = 1) |
22 | densq 15930 | . . . . 5 ⊢ ((√‘𝐴) ∈ ℚ → (denom‘((√‘𝐴)↑2)) = ((denom‘(√‘𝐴))↑2)) | |
23 | 22 | adantl 482 | . . . 4 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘((√‘𝐴)↑2)) = ((denom‘(√‘𝐴))↑2)) |
24 | 10, 21, 23 | 3eqtr2rd 2838 | . . 3 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → ((denom‘(√‘𝐴))↑2) = (1↑2)) |
25 | 3, 4, 6, 8, 24 | sq11d 13476 | . 2 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (denom‘(√‘𝐴)) = 1) |
26 | qden1elz 15931 | . . 3 ⊢ ((√‘𝐴) ∈ ℚ → ((denom‘(√‘𝐴)) = 1 ↔ (√‘𝐴) ∈ ℤ)) | |
27 | 26 | adantl 482 | . 2 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → ((denom‘(√‘𝐴)) = 1 ↔ (√‘𝐴) ∈ ℤ)) |
28 | 25, 27 | mpbid 233 | 1 ⊢ ((𝐴 ∈ ℤ ∧ (√‘𝐴) ∈ ℚ) → (√‘𝐴) ∈ ℤ) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 207 ∧ wa 396 = wceq 1522 ∈ wcel 2081 class class class wbr 4966 ‘cfv 6230 (class class class)co 7021 0cc0 10388 1c1 10389 ≤ cle 10527 ℕcn 11491 2c2 11545 ℤcz 11834 ℚcq 12202 ↑cexp 13284 √csqrt 14431 denomcdenom 15908 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1777 ax-4 1791 ax-5 1888 ax-6 1947 ax-7 1992 ax-8 2083 ax-9 2091 ax-10 2112 ax-11 2126 ax-12 2141 ax-13 2344 ax-ext 2769 ax-sep 5099 ax-nul 5106 ax-pow 5162 ax-pr 5226 ax-un 7324 ax-cnex 10444 ax-resscn 10445 ax-1cn 10446 ax-icn 10447 ax-addcl 10448 ax-addrcl 10449 ax-mulcl 10450 ax-mulrcl 10451 ax-mulcom 10452 ax-addass 10453 ax-mulass 10454 ax-distr 10455 ax-i2m1 10456 ax-1ne0 10457 ax-1rid 10458 ax-rnegex 10459 ax-rrecex 10460 ax-cnre 10461 ax-pre-lttri 10462 ax-pre-lttrn 10463 ax-pre-ltadd 10464 ax-pre-mulgt0 10465 ax-pre-sup 10466 |
This theorem depends on definitions: df-bi 208 df-an 397 df-or 843 df-3or 1081 df-3an 1082 df-tru 1525 df-ex 1762 df-nf 1766 df-sb 2043 df-mo 2576 df-eu 2612 df-clab 2776 df-cleq 2788 df-clel 2863 df-nfc 2935 df-ne 2985 df-nel 3091 df-ral 3110 df-rex 3111 df-reu 3112 df-rmo 3113 df-rab 3114 df-v 3439 df-sbc 3710 df-csb 3816 df-dif 3866 df-un 3868 df-in 3870 df-ss 3878 df-pss 3880 df-nul 4216 df-if 4386 df-pw 4459 df-sn 4477 df-pr 4479 df-tp 4481 df-op 4483 df-uni 4750 df-iun 4831 df-br 4967 df-opab 5029 df-mpt 5046 df-tr 5069 df-id 5353 df-eprel 5358 df-po 5367 df-so 5368 df-fr 5407 df-we 5409 df-xp 5454 df-rel 5455 df-cnv 5456 df-co 5457 df-dm 5458 df-rn 5459 df-res 5460 df-ima 5461 df-pred 6028 df-ord 6074 df-on 6075 df-lim 6076 df-suc 6077 df-iota 6194 df-fun 6232 df-fn 6233 df-f 6234 df-f1 6235 df-fo 6236 df-f1o 6237 df-fv 6238 df-riota 6982 df-ov 7024 df-oprab 7025 df-mpo 7026 df-om 7442 df-1st 7550 df-2nd 7551 df-wrecs 7803 df-recs 7865 df-rdg 7903 df-er 8144 df-en 8363 df-dom 8364 df-sdom 8365 df-sup 8757 df-inf 8758 df-pnf 10528 df-mnf 10529 df-xr 10530 df-ltxr 10531 df-le 10532 df-sub 10724 df-neg 10725 df-div 11151 df-nn 11492 df-2 11553 df-3 11554 df-n0 11751 df-z 11835 df-uz 12099 df-q 12203 df-rp 12245 df-fl 13017 df-mod 13093 df-seq 13225 df-exp 13285 df-cj 14297 df-re 14298 df-im 14299 df-sqrt 14433 df-abs 14434 df-dvds 15446 df-gcd 15682 df-numer 15909 df-denom 15910 |
This theorem is referenced by: nonsq 15933 dchrisum0flblem2 25772 |
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