areacirclem5 - Mathbox for Brendan Leahy

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Theorem areacirclem5 38047

Description: Finding the cross-section of a circle. (Contributed by Brendan Leahy, 31-Aug-2017.) (Revised by Brendan Leahy, 22-Sep-2017.) (Revised by Brendan Leahy, 11-Jul-2018.)

**Hypothesis**
Ref	Expression
areacirc.1	⊢ 𝑆 = {⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}

**Assertion**
Ref	Expression
areacirclem5	⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑆 “ {𝑡}) = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))

Distinct variable groups: 𝑥,𝑦,𝑡,𝑅 𝑡,𝑆 Allowed substitution hints: 𝑆(𝑥,𝑦)

Proof of Theorem areacirclem5 Dummy variable 𝑢 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		areacirc.1	. . . 4 ⊢ 𝑆 = {⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}
2	1	imaeq1i 6016	. . 3 ⊢ (𝑆 “ {𝑡}) = ({⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))} “ {𝑡})
3		vex 3434	. . . 4 ⊢ 𝑡 ∈ V
4		imasng 6043	. . . 4 ⊢ (𝑡 ∈ V → ({⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))} “ {𝑡}) = {𝑢 ∣ 𝑡{⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}𝑢})
5	3, 4	ax-mp 5	. . 3 ⊢ ({⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))} “ {𝑡}) = {𝑢 ∣ 𝑡{⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}𝑢}
6		df-br 5087	. . . . 5 ⊢ (𝑡{⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}𝑢 ↔ ⟨𝑡, 𝑢⟩ ∈ {⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))})
7		vex 3434	. . . . . 6 ⊢ 𝑢 ∈ V
8		eleq1w 2820	. . . . . . . 8 ⊢ (𝑥 = 𝑡 → (𝑥 ∈ ℝ ↔ 𝑡 ∈ ℝ))
9	8	anbi1d 632	. . . . . . 7 ⊢ (𝑥 = 𝑡 → ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ↔ (𝑡 ∈ ℝ ∧ 𝑦 ∈ ℝ)))
10		oveq1 7367	. . . . . . . . 9 ⊢ (𝑥 = 𝑡 → (𝑥↑2) = (𝑡↑2))
11	10	oveq1d 7375	. . . . . . . 8 ⊢ (𝑥 = 𝑡 → ((𝑥↑2) + (𝑦↑2)) = ((𝑡↑2) + (𝑦↑2)))
12	11	breq1d 5096	. . . . . . 7 ⊢ (𝑥 = 𝑡 → (((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2) ↔ ((𝑡↑2) + (𝑦↑2)) ≤ (𝑅↑2)))
13	9, 12	anbi12d 633	. . . . . 6 ⊢ (𝑥 = 𝑡 → (((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2)) ↔ ((𝑡 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑡↑2) + (𝑦↑2)) ≤ (𝑅↑2))))
14		eleq1w 2820	. . . . . . . 8 ⊢ (𝑦 = 𝑢 → (𝑦 ∈ ℝ ↔ 𝑢 ∈ ℝ))
15	14	anbi2d 631	. . . . . . 7 ⊢ (𝑦 = 𝑢 → ((𝑡 ∈ ℝ ∧ 𝑦 ∈ ℝ) ↔ (𝑡 ∈ ℝ ∧ 𝑢 ∈ ℝ)))
16		oveq1 7367	. . . . . . . . 9 ⊢ (𝑦 = 𝑢 → (𝑦↑2) = (𝑢↑2))
17	16	oveq2d 7376	. . . . . . . 8 ⊢ (𝑦 = 𝑢 → ((𝑡↑2) + (𝑦↑2)) = ((𝑡↑2) + (𝑢↑2)))
18	17	breq1d 5096	. . . . . . 7 ⊢ (𝑦 = 𝑢 → (((𝑡↑2) + (𝑦↑2)) ≤ (𝑅↑2) ↔ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))
19	15, 18	anbi12d 633	. . . . . 6 ⊢ (𝑦 = 𝑢 → (((𝑡 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑡↑2) + (𝑦↑2)) ≤ (𝑅↑2)) ↔ ((𝑡 ∈ ℝ ∧ 𝑢 ∈ ℝ) ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))))
20	3, 7, 13, 19	opelopab 5490	. . . . 5 ⊢ (⟨𝑡, 𝑢⟩ ∈ {⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))} ↔ ((𝑡 ∈ ℝ ∧ 𝑢 ∈ ℝ) ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))
21		anass 468	. . . . 5 ⊢ (((𝑡 ∈ ℝ ∧ 𝑢 ∈ ℝ) ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)) ↔ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))))
22	6, 20, 21	3bitri 297	. . . 4 ⊢ (𝑡{⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}𝑢 ↔ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))))
23	22	abbii 2804	. . 3 ⊢ {𝑢 ∣ 𝑡{⟨𝑥, 𝑦⟩ ∣ ((𝑥 ∈ ℝ ∧ 𝑦 ∈ ℝ) ∧ ((𝑥↑2) + (𝑦↑2)) ≤ (𝑅↑2))}𝑢} = {𝑢 ∣ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))}
24	2, 5, 23	3eqtri 2764	. 2 ⊢ (𝑆 “ {𝑡}) = {𝑢 ∣ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))}
25		simp3 1139	. . . . 5 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → 𝑡 ∈ ℝ)
26	25	biantrurd 532	. . . 4 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)) ↔ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))))
27	26	abbidv 2803	. . 3 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = {𝑢 ∣ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))})
28		resqcl 14077	. . . . . . . . . . . 12 ⊢ (𝑅 ∈ ℝ → (𝑅↑2) ∈ ℝ)
29	28	3ad2ant1 1134	. . . . . . . . . . 11 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑅↑2) ∈ ℝ)
30		resqcl 14077	. . . . . . . . . . . 12 ⊢ (𝑡 ∈ ℝ → (𝑡↑2) ∈ ℝ)
31	30	3ad2ant3 1136	. . . . . . . . . . 11 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑡↑2) ∈ ℝ)
32	29, 31	resubcld 11569	. . . . . . . . . 10 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((𝑅↑2) − (𝑡↑2)) ∈ ℝ)
33	32	adantr 480	. . . . . . . . 9 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑅↑2) − (𝑡↑2)) ∈ ℝ)
34		absresq 15255	. . . . . . . . . . . . 13 ⊢ (𝑡 ∈ ℝ → ((abs‘𝑡)↑2) = (𝑡↑2))
35	34	3ad2ant3 1136	. . . . . . . . . . . 12 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((abs‘𝑡)↑2) = (𝑡↑2))
36	35	breq1d 5096	. . . . . . . . . . 11 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (((abs‘𝑡)↑2) ≤ (𝑅↑2) ↔ (𝑡↑2) ≤ (𝑅↑2)))
37		recn 11119	. . . . . . . . . . . . . 14 ⊢ (𝑡 ∈ ℝ → 𝑡 ∈ ℂ)
38	37	abscld 15392	. . . . . . . . . . . . 13 ⊢ (𝑡 ∈ ℝ → (abs‘𝑡) ∈ ℝ)
39	38	3ad2ant3 1136	. . . . . . . . . . . 12 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (abs‘𝑡) ∈ ℝ)
40		simp1 1137	. . . . . . . . . . . 12 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → 𝑅 ∈ ℝ)
41	37	absge0d 15400	. . . . . . . . . . . . 13 ⊢ (𝑡 ∈ ℝ → 0 ≤ (abs‘𝑡))
42	41	3ad2ant3 1136	. . . . . . . . . . . 12 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → 0 ≤ (abs‘𝑡))
43		simp2 1138	. . . . . . . . . . . 12 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → 0 ≤ 𝑅)
44	39, 40, 42, 43	le2sqd 14210	. . . . . . . . . . 11 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((abs‘𝑡) ≤ 𝑅 ↔ ((abs‘𝑡)↑2) ≤ (𝑅↑2)))
45	29, 31	subge0d 11731	. . . . . . . . . . 11 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (0 ≤ ((𝑅↑2) − (𝑡↑2)) ↔ (𝑡↑2) ≤ (𝑅↑2)))
46	36, 44, 45	3bitr4d 311	. . . . . . . . . 10 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((abs‘𝑡) ≤ 𝑅 ↔ 0 ≤ ((𝑅↑2) − (𝑡↑2))))
47	46	biimpa 476	. . . . . . . . 9 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → 0 ≤ ((𝑅↑2) − (𝑡↑2)))
48	33, 47	resqrtcld 15371	. . . . . . . 8 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ)
49	48	renegcld 11568	. . . . . . 7 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → -(√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ)
50	49	rexrd 11186	. . . . . 6 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → -(√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ^*)
51	48	rexrd 11186	. . . . . 6 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ^*)
52		iccval 13328	. . . . . 6 ⊢ ((-(√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ^* ∧ (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ^) → (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))) = {𝑢 ∈ ℝ^ ∣ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))})
53	50, 51, 52	syl2anc 585	. . . . 5 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))) = {𝑢 ∈ ℝ^* ∣ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))})
54		iftrue 4473	. . . . . 6 ⊢ ((abs‘𝑡) ≤ 𝑅 → if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅) = (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))))
55	54	adantl 481	. . . . 5 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅) = (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))))
56		absresq 15255	. . . . . . . . . . . 12 ⊢ (𝑢 ∈ ℝ → ((abs‘𝑢)↑2) = (𝑢↑2))
57	32	recnd 11164	. . . . . . . . . . . . . 14 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((𝑅↑2) − (𝑡↑2)) ∈ ℂ)
58	57	adantr 480	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑅↑2) − (𝑡↑2)) ∈ ℂ)
59	58	sqsqrtd 15395	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((√‘((𝑅↑2) − (𝑡↑2)))↑2) = ((𝑅↑2) − (𝑡↑2)))
60	56, 59	breqan12rd 5103	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (((abs‘𝑢)↑2) ≤ ((√‘((𝑅↑2) − (𝑡↑2)))↑2) ↔ (𝑢↑2) ≤ ((𝑅↑2) − (𝑡↑2))))
61		recn 11119	. . . . . . . . . . . . . 14 ⊢ (𝑢 ∈ ℝ → 𝑢 ∈ ℂ)
62	61	abscld 15392	. . . . . . . . . . . . 13 ⊢ (𝑢 ∈ ℝ → (abs‘𝑢) ∈ ℝ)
63	62	adantl 481	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (abs‘𝑢) ∈ ℝ)
64	48	adantr 480	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ)
65	61	absge0d 15400	. . . . . . . . . . . . 13 ⊢ (𝑢 ∈ ℝ → 0 ≤ (abs‘𝑢))
66	65	adantl 481	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → 0 ≤ (abs‘𝑢))
67	33, 47	sqrtge0d 15374	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → 0 ≤ (√‘((𝑅↑2) − (𝑡↑2))))
68	67	adantr 480	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → 0 ≤ (√‘((𝑅↑2) − (𝑡↑2))))
69	63, 64, 66, 68	le2sqd 14210	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → ((abs‘𝑢) ≤ (√‘((𝑅↑2) − (𝑡↑2))) ↔ ((abs‘𝑢)↑2) ≤ ((√‘((𝑅↑2) − (𝑡↑2)))↑2)))
70	31	adantr 480	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑢 ∈ ℝ) → (𝑡↑2) ∈ ℝ)
71		resqcl 14077	. . . . . . . . . . . . . 14 ⊢ (𝑢 ∈ ℝ → (𝑢↑2) ∈ ℝ)
72	71	adantl 481	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑢 ∈ ℝ) → (𝑢↑2) ∈ ℝ)
73	29	adantr 480	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑢 ∈ ℝ) → (𝑅↑2) ∈ ℝ)
74	70, 72, 73	leaddsub2d 11743	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑢 ∈ ℝ) → (((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2) ↔ (𝑢↑2) ≤ ((𝑅↑2) − (𝑡↑2))))
75	74	adantlr 716	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2) ↔ (𝑢↑2) ≤ ((𝑅↑2) − (𝑡↑2))))
76	60, 69, 75	3bitr4rd 312	. . . . . . . . . 10 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2) ↔ (abs‘𝑢) ≤ (√‘((𝑅↑2) − (𝑡↑2)))))
77		simpr 484	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → 𝑢 ∈ ℝ)
78	77, 64	absled 15386	. . . . . . . . . 10 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → ((abs‘𝑢) ≤ (√‘((𝑅↑2) − (𝑡↑2))) ↔ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))))
79		rexr 11182	. . . . . . . . . . . 12 ⊢ (𝑢 ∈ ℝ → 𝑢 ∈ ℝ^*)
80	79	adantl 481	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → 𝑢 ∈ ℝ^*)
81	80	biantrurd 532	. . . . . . . . . 10 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → ((-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))) ↔ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))))
82	76, 78, 81	3bitrd 305	. . . . . . . . 9 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ 𝑢 ∈ ℝ) → (((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2) ↔ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))))
83	82	pm5.32da 579	. . . . . . . 8 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)) ↔ (𝑢 ∈ ℝ ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))))))
84		simprl 771	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → 𝑢 ∈ ℝ^*)
85	48	adantr 480	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ)
86		mnfxr 11193	. . . . . . . . . . . . 13 ⊢ -∞ ∈ ℝ^*
87	86	a1i 11	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -∞ ∈ ℝ^*)
88	49	adantr 480	. . . . . . . . . . . . 13 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -(√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ)
89	88	rexrd 11186	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -(√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ^*)
90	49	mnfltd 13066	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → -∞ < -(√‘((𝑅↑2) − (𝑡↑2))))
91	90	adantr 480	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -∞ < -(√‘((𝑅↑2) − (𝑡↑2))))
92		simprrl 781	. . . . . . . . . . . 12 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢)
93	87, 89, 84, 91, 92	xrltletrd 13103	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → -∞ < 𝑢)
94		simprrr 782	. . . . . . . . . . 11 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))
95		xrre 13112	. . . . . . . . . . 11 ⊢ (((𝑢 ∈ ℝ^* ∧ (√‘((𝑅↑2) − (𝑡↑2))) ∈ ℝ) ∧ (-∞ < 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))) → 𝑢 ∈ ℝ)
96	84, 85, 93, 94, 95	syl22anc 839	. . . . . . . . . 10 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))) → 𝑢 ∈ ℝ)
97	96	ex 412	. . . . . . . . 9 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))) → 𝑢 ∈ ℝ))
98	97	pm4.71rd 562	. . . . . . . 8 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))) ↔ (𝑢 ∈ ℝ ∧ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))))))
99	83, 98	bitr4d 282	. . . . . . 7 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → ((𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)) ↔ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))))
100	99	abbidv 2803	. . . . . 6 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = {𝑢 ∣ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))})
101		df-rab 3391	. . . . . 6 ⊢ {𝑢 ∈ ℝ^* ∣ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))} = {𝑢 ∣ (𝑢 ∈ ℝ^* ∧ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2)))))}
102	100, 101	eqtr4di 2790	. . . . 5 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = {𝑢 ∈ ℝ^* ∣ (-(√‘((𝑅↑2) − (𝑡↑2))) ≤ 𝑢 ∧ 𝑢 ≤ (√‘((𝑅↑2) − (𝑡↑2))))})
103	53, 55, 102	3eqtr4rd 2783	. . . 4 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ (abs‘𝑡) ≤ 𝑅) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))
104	40, 39	ltnled 11284	. . . . . . . 8 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑅 < (abs‘𝑡) ↔ ¬ (abs‘𝑡) ≤ 𝑅))
105	104	biimprd 248	. . . . . . 7 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (¬ (abs‘𝑡) ≤ 𝑅 → 𝑅 < (abs‘𝑡)))
106	105	imdistani 568	. . . . . 6 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ ¬ (abs‘𝑡) ≤ 𝑅) → ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)))
107		df-rab 3391	. . . . . . 7 ⊢ {𝑢 ∈ ℝ ∣ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)} = {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))}
108	29	3ad2ant1 1134	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑅↑2) ∈ ℝ)
109	31	3ad2ant1 1134	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑡↑2) ∈ ℝ)
110	71	3ad2ant3 1136	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑢↑2) ∈ ℝ)
111	109, 110	readdcld 11165	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → ((𝑡↑2) + (𝑢↑2)) ∈ ℝ)
112	40, 39, 43, 42	lt2sqd 14209	. . . . . . . . . . . . . . 15 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑅 < (abs‘𝑡) ↔ (𝑅↑2) < ((abs‘𝑡)↑2)))
113	35	breq2d 5098	. . . . . . . . . . . . . . 15 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → ((𝑅↑2) < ((abs‘𝑡)↑2) ↔ (𝑅↑2) < (𝑡↑2)))
114	112, 113	bitrd 279	. . . . . . . . . . . . . 14 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑅 < (abs‘𝑡) ↔ (𝑅↑2) < (𝑡↑2)))
115	114	biimpa 476	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)) → (𝑅↑2) < (𝑡↑2))
116	115	3adant3 1133	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑅↑2) < (𝑡↑2))
117		sqge0 14089	. . . . . . . . . . . . . 14 ⊢ (𝑢 ∈ ℝ → 0 ≤ (𝑢↑2))
118	117	3ad2ant3 1136	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → 0 ≤ (𝑢↑2))
119	109, 110	addge01d 11729	. . . . . . . . . . . . 13 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (0 ≤ (𝑢↑2) ↔ (𝑡↑2) ≤ ((𝑡↑2) + (𝑢↑2))))
120	118, 119	mpbid 232	. . . . . . . . . . . 12 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑡↑2) ≤ ((𝑡↑2) + (𝑢↑2)))
121	108, 109, 111, 116, 120	ltletrd 11297	. . . . . . . . . . 11 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → (𝑅↑2) < ((𝑡↑2) + (𝑢↑2)))
122	108, 111	ltnled 11284	. . . . . . . . . . 11 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → ((𝑅↑2) < ((𝑡↑2) + (𝑢↑2)) ↔ ¬ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))
123	121, 122	mpbid 232	. . . . . . . . . 10 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡) ∧ 𝑢 ∈ ℝ) → ¬ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))
124	123	3expa 1119	. . . . . . . . 9 ⊢ ((((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)) ∧ 𝑢 ∈ ℝ) → ¬ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))
125	124	ralrimiva 3130	. . . . . . . 8 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)) → ∀𝑢 ∈ ℝ ¬ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))
126		rabeq0 4329	. . . . . . . 8 ⊢ ({𝑢 ∈ ℝ ∣ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)} = ∅ ↔ ∀𝑢 ∈ ℝ ¬ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))
127	125, 126	sylibr 234	. . . . . . 7 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)) → {𝑢 ∈ ℝ ∣ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)} = ∅)
128	107, 127	eqtr3id 2786	. . . . . 6 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ 𝑅 < (abs‘𝑡)) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = ∅)
129	106, 128	syl 17	. . . . 5 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ ¬ (abs‘𝑡) ≤ 𝑅) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = ∅)
130		iffalse 4476	. . . . . 6 ⊢ (¬ (abs‘𝑡) ≤ 𝑅 → if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅) = ∅)
131	130	adantl 481	. . . . 5 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ ¬ (abs‘𝑡) ≤ 𝑅) → if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅) = ∅)
132	129, 131	eqtr4d 2775	. . . 4 ⊢ (((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) ∧ ¬ (abs‘𝑡) ≤ 𝑅) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))
133	103, 132	pm2.61dan 813	. . 3 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → {𝑢 ∣ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2))} = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))
134	27, 133	eqtr3d 2774	. 2 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → {𝑢 ∣ (𝑡 ∈ ℝ ∧ (𝑢 ∈ ℝ ∧ ((𝑡↑2) + (𝑢↑2)) ≤ (𝑅↑2)))} = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))
135	24, 134	eqtrid 2784	1 ⊢ ((𝑅 ∈ ℝ ∧ 0 ≤ 𝑅 ∧ 𝑡 ∈ ℝ) → (𝑆 “ {𝑡}) = if((abs‘𝑡) ≤ 𝑅, (-(√‘((𝑅↑2) − (𝑡↑2)))[,](√‘((𝑅↑2) − (𝑡↑2)))), ∅))

Colors of variables: wff setvar class

Syntax hints: ¬ wn 3 → wi 4 ↔ wb 206 ∧ wa 395 ∧ w3a 1087 = wceq 1542 ∈ wcel 2114 {cab 2715 ∀wral 3052 {crab 3390 Vcvv 3430 ∅c0 4274 ifcif 4467 {csn 4568 ⟨cop 4574 class class class wbr 5086 {copab 5148 “ cima 5627 ‘cfv 6492 (class class class)co 7360 ℂcc 11027 ℝcr 11028 0cc0 11029 + caddc 11032 -∞cmnf 11168 ℝ^*cxr 11169 < clt 11170 ≤ cle 11171 − cmin 11368 -cneg 11369 2c2 12227 [,]cicc 13292 ↑cexp 14014 √csqrt 15186 abscabs 15187

This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1912 ax-6 1969 ax-7 2010 ax-8 2116 ax-9 2124 ax-10 2147 ax-11 2163 ax-12 2185 ax-ext 2709 ax-sep 5231 ax-nul 5241 ax-pow 5302 ax-pr 5370 ax-un 7682 ax-cnex 11085 ax-resscn 11086 ax-1cn 11087 ax-icn 11088 ax-addcl 11089 ax-addrcl 11090 ax-mulcl 11091 ax-mulrcl 11092 ax-mulcom 11093 ax-addass 11094 ax-mulass 11095 ax-distr 11096 ax-i2m1 11097 ax-1ne0 11098 ax-1rid 11099 ax-rnegex 11100 ax-rrecex 11101 ax-cnre 11102 ax-pre-lttri 11103 ax-pre-lttrn 11104 ax-pre-ltadd 11105 ax-pre-mulgt0 11106 ax-pre-sup 11107

This theorem depends on definitions: df-bi 207 df-an 396 df-or 849 df-3or 1088 df-3an 1089 df-tru 1545 df-fal 1555 df-ex 1782 df-nf 1786 df-sb 2069 df-mo 2540 df-eu 2570 df-clab 2716 df-cleq 2729 df-clel 2812 df-nfc 2886 df-ne 2934 df-nel 3038 df-ral 3053 df-rex 3063 df-rmo 3343 df-reu 3344 df-rab 3391 df-v 3432 df-sbc 3730 df-csb 3839 df-dif 3893 df-un 3895 df-in 3897 df-ss 3907 df-pss 3910 df-nul 4275 df-if 4468 df-pw 4544 df-sn 4569 df-pr 4571 df-op 4575 df-uni 4852 df-iun 4936 df-br 5087 df-opab 5149 df-mpt 5168 df-tr 5194 df-id 5519 df-eprel 5524 df-po 5532 df-so 5533 df-fr 5577 df-we 5579 df-xp 5630 df-rel 5631 df-cnv 5632 df-co 5633 df-dm 5634 df-rn 5635 df-res 5636 df-ima 5637 df-pred 6259 df-ord 6320 df-on 6321 df-lim 6322 df-suc 6323 df-iota 6448 df-fun 6494 df-fn 6495 df-f 6496 df-f1 6497 df-fo 6498 df-f1o 6499 df-fv 6500 df-riota 7317 df-ov 7363 df-oprab 7364 df-mpo 7365 df-om 7811 df-2nd 7936 df-frecs 8224 df-wrecs 8255 df-recs 8304 df-rdg 8342 df-er 8636 df-en 8887 df-dom 8888 df-sdom 8889 df-sup 9348 df-pnf 11172 df-mnf 11173 df-xr 11174 df-ltxr 11175 df-le 11176 df-sub 11370 df-neg 11371 df-div 11799 df-nn 12166 df-2 12235 df-3 12236 df-n0 12429 df-z 12516 df-uz 12780 df-rp 12934 df-icc 13296 df-seq 13955 df-exp 14015 df-cj 15052 df-re 15053 df-im 15054 df-sqrt 15188 df-abs 15189

This theorem is referenced by: areacirc 38048

W3C validator