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Theorem efifolem6 8642
Description: Lemma for efifo 8644.
Assertion
Ref Expression
efifolem6 |- ((X e. RR /\ Y e. RR /\ ((X^2) + (Y^2)) = 1) -> (Y = 0 -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a))))
Distinct variable groups:   X,a   Y,a

Proof of Theorem efifolem6
StepHypRef Expression
1 sq0i 6567 . . . . . . . . . . 11 |- (Y = 0 -> (Y^2) = 0)
21opreq2d 3961 . . . . . . . . . 10 |- (Y = 0 -> ((X^2) + (Y^2)) = ((X^2) + 0))
3 recnt 5285 . . . . . . . . . . 11 |- (X e. RR -> X e. CC)
4 sqclt 6542 . . . . . . . . . . 11 |- (X e. CC -> (X^2) e. CC)
5 ax0id 5253 . . . . . . . . . . 11 |- ((X^2) e. CC -> ((X^2) + 0) = (X^2))
63, 4, 53syl 20 . . . . . . . . . 10 |- (X e. RR -> ((X^2) + 0) = (X^2))
72, 6sylan9eqr 1521 . . . . . . . . 9 |- ((X e. RR /\ Y = 0) -> ((X^2) + (Y^2)) = (X^2))
87eqeq1d 1475 . . . . . . . 8 |- ((X e. RR /\ Y = 0) -> (((X^2) + (Y^2)) = 1 <-> (X^2) = 1))
9 ax1cn 5241 . . . . . . . . . . . 12 |- 1 e. CC
10 sqeqort 6580 . . . . . . . . . . . 12 |- ((X e. CC /\ 1 e. CC) -> ((X^2) = (1^2) <-> (X = 1 \/ X = -u1)))
119, 10mpan2 694 . . . . . . . . . . 11 |- (X e. CC -> ((X^2) = (1^2) <-> (X = 1 \/ X = -u1)))
123, 11syl 10 . . . . . . . . . 10 |- (X e. RR -> ((X^2) = (1^2) <-> (X = 1 \/ X = -u1)))
13 sq1 6568 . . . . . . . . . . 11 |- (1^2) = 1
1413eqeq2i 1477 . . . . . . . . . 10 |- ((X^2) = (1^2) <-> (X^2) = 1)
1512, 14syl5bbr 532 . . . . . . . . 9 |- (X e. RR -> ((X^2) = 1 <-> (X = 1 \/ X = -u1)))
1615adantr 389 . . . . . . . 8 |- ((X e. RR /\ Y = 0) -> ((X^2) = 1 <-> (X = 1 \/ X = -u1)))
178, 16bitrd 526 . . . . . . 7 |- ((X e. RR /\ Y = 0) -> (((X^2) + (Y^2)) = 1 <-> (X = 1 \/ X = -u1)))
1817ex 373 . . . . . 6 |- (X e. RR -> (Y = 0 -> (((X^2) + (Y^2)) = 1 <-> (X = 1 \/ X = -u1))))
1918pm5.32rd 646 . . . . 5 |- (X e. RR -> ((((X^2) + (Y^2)) = 1 /\ Y = 0) <-> ((X = 1 \/ X = -u1) /\ Y = 0)))
20 0re 5412 . . . . . . . . 9 |- 0 e. RR
2120leid 5584 . . . . . . . . 9 |- 0 <_ 0
22 2re 5926 . . . . . . . . . 10 |- 2 e. RR
23 pire 8596 . . . . . . . . . 10 |- pi e. RR
24 2pos 5936 . . . . . . . . . 10 |- 0 < 2
25 pipos 8597 . . . . . . . . . 10 |- 0 < pi
2622, 23, 24, 25mulgt0i 5582 . . . . . . . . 9 |- 0 < (2 x. pi)
2722, 23remulcl 5307 . . . . . . . . . . 11 |- (2 x. pi) e. RR
28 elico2t 6323 . . . . . . . . . . 11 |- ((0 e. RR /\ (2 x. pi) e. RR) -> (0 e. (0[,)(2 x. pi)) <-> (0 e. RR /\ 0 <_ 0 /\ 0 < (2 x. pi))))
2920, 27, 28mp2an 695 . . . . . . . . . 10 |- (0 e. (0[,)(2 x. pi)) <-> (0 e. RR /\ 0 <_ 0 /\ 0 < (2 x. pi)))
3029biimpr 152 . . . . . . . . 9 |- ((0 e. RR /\ 0 <_ 0 /\ 0 < (2 x. pi)) -> 0 e. (0[,)(2 x. pi)))
3120, 21, 26, 30mp3an 913 . . . . . . . 8 |- 0 e. (0[,)(2 x. pi))
32 fveq2 3709 . . . . . . . . . . 11 |- (a = 0 -> (cos` a) = (cos`
0))
3332eqeq2d 1478 . . . . . . . . . 10 |- (a = 0 -> (X = (cos` a) <-> X = (cos`
0)))
34 fveq2 3709 . . . . . . . . . . 11 |- (a = 0 -> (sin` a) = (sin`
0))
3534eqeq2d 1478 . . . . . . . . . 10 |- (a = 0 -> (Y = (sin` a) <-> Y = (sin`
0)))
3633, 35anbi12d 626 . . . . . . . . 9 |- (a = 0 -> ((X = (cos` a) /\ Y = (sin` a)) <-> (X = (cos` 0) /\ Y = (sin` 0))))
3736rcla4ev 1868 . . . . . . . 8 |- ((0 e. (0[,)(2 x. pi)) /\ (X = (cos` 0) /\ Y = (sin` 0))) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
3831, 37mpan 693 . . . . . . 7 |- ((X = (cos` 0) /\ Y = (sin` 0)) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
39 cos0 7388 . . . . . . . . 9 |- (cos` 0) = 1
40 eqeq2 1476 . . . . . . . . 9 |- (X = 1 -> ((cos` 0) = X <-> (cos` 0) = 1))
4139, 40mpbiri 194 . . . . . . . 8 |- (X = 1 -> (cos` 0) = X)
4241eqcomd 1472 . . . . . . 7 |- (X = 1 -> X = (cos`
0))
43 sin0 7386 . . . . . . . . 9 |- (sin` 0) = 0
44 eqeq2 1476 . . . . . . . . 9 |- (Y = 0 -> ((sin` 0) = Y <-> (sin` 0) = 0))
4543, 44mpbiri 194 . . . . . . . 8 |- (Y = 0 -> (sin` 0) = Y)
4645eqcomd 1472 . . . . . . 7 |- (Y = 0 -> Y = (sin`
0))
4738, 42, 46syl2an 454 . . . . . 6 |- ((X = 1 /\ Y = 0) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
4820, 23, 25ltlei 5554 . . . . . . . . 9 |- 0 <_ pi
4923recn 5286 . . . . . . . . . . 11 |- pi e. CC
5049mulid2 5305 . . . . . . . . . 10 |- (1 x. pi) = pi
51 1lt2 5975 . . . . . . . . . . 11 |- 1 < 2
52 1re 5407 . . . . . . . . . . . 12 |- 1 e. RR
5352, 22, 23, 25ltmul1i 5777 . . . . . . . . . . 11 |- (1 < 2 <-> (1 x. pi) < (2 x. pi))
5451, 53mpbi 189 . . . . . . . . . 10 |- (1 x. pi) < (2 x. pi)
5550, 54eqbrtrr 2626 . . . . . . . . 9 |- pi < (2 x. pi)
56 elico2t 6323 . . . . . . . . . . 11 |- ((0 e. RR /\ (2 x. pi) e. RR) -> (pi e. (0[,)(2 x. pi)) <-> (pi e. RR /\ 0 <_ pi /\ pi < (2 x. pi))))
5720, 27, 56mp2an 695 . . . . . . . . . 10 |- (pi e. (0[,)(2 x. pi)) <-> (pi e. RR /\ 0 <_ pi /\ pi < (2 x. pi)))
5857biimpr 152 . . . . . . . . 9 |- ((pi e. RR /\ 0 <_ pi /\ pi < (2 x. pi)) -> pi e. (0[,)(2 x. pi)))
5923, 48, 55, 58mp3an 913 . . . . . . . 8 |- pi e. (0[,)(2 x. pi))
60 fveq2 3709 . . . . . . . . . . 11 |- (a = pi -> (cos` a) = (cos`
pi))
6160eqeq2d 1478 . . . . . . . . . 10 |- (a = pi -> (X = (cos` a) <-> X = (cos`
pi)))
62 fveq2 3709 . . . . . . . . . . 11 |- (a = pi -> (sin` a) = (sin`
pi))
6362eqeq2d 1478 . . . . . . . . . 10 |- (a = pi -> (Y = (sin` a) <-> Y = (sin`
pi)))
6461, 63anbi12d 626 . . . . . . . . 9 |- (a = pi -> ((X = (cos` a) /\ Y = (sin` a)) <-> (X = (cos` pi) /\ Y = (sin` pi))))
6564rcla4ev 1868 . . . . . . . 8 |- ((pi e. (0[,)(2 x. pi)) /\ (X = (cos` pi) /\ Y = (sin` pi))) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
6659, 65mpan 693 . . . . . . 7 |- ((X = (cos` pi) /\ Y = (sin` pi)) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
67 cospi 8601 . . . . . . . . 9 |- (cos` pi) = -u1
68 eqeq2 1476 . . . . . . . . 9 |- (X = -u1 -> ((cos` pi) = X <-> (cos` pi) = -u1))
6967, 68mpbiri 194 . . . . . . . 8 |- (X = -u1 -> (cos` pi) = X)
7069eqcomd 1472 . . . . . . 7 |- (X = -u1 -> X = (cos` pi))
71 sinpi 8595 . . . . . . . . 9 |- (sin` pi) = 0
72 eqeq2 1476 . . . . . . . . 9 |- (Y = 0 -> ((sin` pi) = Y <-> (sin` pi) = 0))
7371, 72mpbiri 194 . . . . . . . 8 |- (Y = 0 -> (sin` pi) = Y)
7473eqcomd 1472 . . . . . . 7 |- (Y = 0 -> Y = (sin`
pi))
7566, 70, 74syl2an 454 . . . . . 6 |- ((X = -u1 /\ Y = 0) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
7647, 75jaoian 425 . . . . 5 |- (((X = 1 \/ X = -u1) /\ Y = 0) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
7719, 76syl6bi 214 . . . 4 |- (X e. RR -> ((((X^2) + (Y^2)) = 1 /\ Y = 0) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a))))
78773impib 829 . . 3 |- ((X e. RR /\ ((X^2) + (Y^2)) = 1 /\ Y = 0) -> E.a e. (0[,)(2 x. pi))(X = (cos` a) /\ Y = (sin` a)))
79783expia 833 . 2 |- ((X e. RR /\ ((X^2) + (Y^2)) = 1) -> (Y = 0 -> E.a e. (0[,)(2 x. pi))(X =