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Theorem subsq 10285

Description: Factor the difference of two squares. (Contributed by NM, 21-Feb-2008.)

**Assertion**
Ref	Expression
subsq	⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴↑2) − (𝐵↑2)) = ((𝐴 + 𝐵) · (𝐴 − 𝐵)))

**Proof of Theorem subsq**
Step	Hyp	Ref	Expression
1		simpl 108	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → 𝐴 ∈ ℂ)
2		simpr 109	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → 𝐵 ∈ ℂ)
3		subcl 7877	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 − 𝐵) ∈ ℂ)
4	1, 2, 3	adddird 7708	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴 + 𝐵) · (𝐴 − 𝐵)) = ((𝐴 · (𝐴 − 𝐵)) + (𝐵 · (𝐴 − 𝐵))))
5		subdi 8059	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 · (𝐴 − 𝐵)) = ((𝐴 · 𝐴) − (𝐴 · 𝐵)))
6	5	3anidm12 1254	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 · (𝐴 − 𝐵)) = ((𝐴 · 𝐴) − (𝐴 · 𝐵)))
7		sqval 10237	. . . . . 6 ⊢ (𝐴 ∈ ℂ → (𝐴↑2) = (𝐴 · 𝐴))
8	7	adantr 272	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴↑2) = (𝐴 · 𝐴))
9	8	oveq1d 5741	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴↑2) − (𝐴 · 𝐵)) = ((𝐴 · 𝐴) − (𝐴 · 𝐵)))
10	6, 9	eqtr4d 2148	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 · (𝐴 − 𝐵)) = ((𝐴↑2) − (𝐴 · 𝐵)))
11	2, 1, 2	subdid 8088	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐵 · (𝐴 − 𝐵)) = ((𝐵 · 𝐴) − (𝐵 · 𝐵)))
12		mulcom 7666	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 · 𝐵) = (𝐵 · 𝐴))
13		sqval 10237	. . . . . 6 ⊢ (𝐵 ∈ ℂ → (𝐵↑2) = (𝐵 · 𝐵))
14	13	adantl 273	. . . . 5 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐵↑2) = (𝐵 · 𝐵))
15	12, 14	oveq12d 5744	. . . 4 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴 · 𝐵) − (𝐵↑2)) = ((𝐵 · 𝐴) − (𝐵 · 𝐵)))
16	11, 15	eqtr4d 2148	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐵 · (𝐴 − 𝐵)) = ((𝐴 · 𝐵) − (𝐵↑2)))
17	10, 16	oveq12d 5744	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴 · (𝐴 − 𝐵)) + (𝐵 · (𝐴 − 𝐵))) = (((𝐴↑2) − (𝐴 · 𝐵)) + ((𝐴 · 𝐵) − (𝐵↑2))))
18		sqcl 10240	. . . 4 ⊢ (𝐴 ∈ ℂ → (𝐴↑2) ∈ ℂ)
19	18	adantr 272	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴↑2) ∈ ℂ)
20		mulcl 7664	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐴 · 𝐵) ∈ ℂ)
21		sqcl 10240	. . . 4 ⊢ (𝐵 ∈ ℂ → (𝐵↑2) ∈ ℂ)
22	21	adantl 273	. . 3 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (𝐵↑2) ∈ ℂ)
23	19, 20, 22	npncand 8013	. 2 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → (((𝐴↑2) − (𝐴 · 𝐵)) + ((𝐴 · 𝐵) − (𝐵↑2))) = ((𝐴↑2) − (𝐵↑2)))
24	4, 17, 23	3eqtrrd 2150	1 ⊢ ((𝐴 ∈ ℂ ∧ 𝐵 ∈ ℂ) → ((𝐴↑2) − (𝐵↑2)) = ((𝐴 + 𝐵) · (𝐴 − 𝐵)))

Colors of variables: wff set class

Syntax hints: → wi 4 ∧ wa 103 = wceq 1312 ∈ wcel 1461 (class class class)co 5726 ℂcc 7538 + caddc 7543 · cmul 7545 − cmin 7849 2c2 8674 ↑cexp 10178

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 586 ax-in2 587 ax-io 681 ax-5 1404 ax-7 1405 ax-gen 1406 ax-ie1 1450 ax-ie2 1451 ax-8 1463 ax-10 1464 ax-11 1465 ax-i12 1466 ax-bndl 1467 ax-4 1468 ax-13 1472 ax-14 1473 ax-17 1487 ax-i9 1491 ax-ial 1495 ax-i5r 1496 ax-ext 2095 ax-coll 4001 ax-sep 4004 ax-nul 4012 ax-pow 4056 ax-pr 4089 ax-un 4313 ax-setind 4410 ax-iinf 4460 ax-cnex 7629 ax-resscn 7630 ax-1cn 7631 ax-1re 7632 ax-icn 7633 ax-addcl 7634 ax-addrcl 7635 ax-mulcl 7636 ax-mulrcl 7637 ax-addcom 7638 ax-mulcom 7639 ax-addass 7640 ax-mulass 7641 ax-distr 7642 ax-i2m1 7643 ax-0lt1 7644 ax-1rid 7645 ax-0id 7646 ax-rnegex 7647 ax-precex 7648 ax-cnre 7649 ax-pre-ltirr 7650 ax-pre-ltwlin 7651 ax-pre-lttrn 7652 ax-pre-apti 7653 ax-pre-ltadd 7654 ax-pre-mulgt0 7655 ax-pre-mulext 7656

This theorem depends on definitions: df-bi 116 df-dc 803 df-3or 944 df-3an 945 df-tru 1315 df-fal 1318 df-nf 1418 df-sb 1717 df-eu 1976 df-mo 1977 df-clab 2100 df-cleq 2106 df-clel 2109 df-nfc 2242 df-ne 2281 df-nel 2376 df-ral 2393 df-rex 2394 df-reu 2395 df-rmo 2396 df-rab 2397 df-v 2657 df-sbc 2877 df-csb 2970 df-dif 3037 df-un 3039 df-in 3041 df-ss 3048 df-nul 3328 df-if 3439 df-pw 3476 df-sn 3497 df-pr 3498 df-op 3500 df-uni 3701 df-int 3736 df-iun 3779 df-br 3894 df-opab 3948 df-mpt 3949 df-tr 3985 df-id 4173 df-po 4176 df-iso 4177 df-iord 4246 df-on 4248 df-ilim 4249 df-suc 4251 df-iom 4463 df-xp 4503 df-rel 4504 df-cnv 4505 df-co 4506 df-dm 4507 df-rn 4508 df-res 4509 df-ima 4510 df-iota 5044 df-fun 5081 df-fn 5082 df-f 5083 df-f1 5084 df-fo 5085 df-f1o 5086 df-fv 5087 df-riota 5682 df-ov 5729 df-oprab 5730 df-mpo 5731 df-1st 5989 df-2nd 5990 df-recs 6153 df-frec 6239 df-pnf 7719 df-mnf 7720 df-xr 7721 df-ltxr 7722 df-le 7723 df-sub 7851 df-neg 7852 df-reap 8248 df-ap 8255 df-div 8339 df-inn 8624 df-2 8682 df-n0 8875 df-z 8952 df-uz 9222 df-seqfrec 10105 df-exp 10179

This theorem is referenced by: subsq2 10286 subsqi 10288 resqrexlemnm 10675 resqrexlemglsq 10679

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