Step |
Hyp |
Ref |
Expression |
1 |
|
tan4thpi |
|- ( tan ` ( _pi / 4 ) ) = 1 |
2 |
1
|
fveq2i |
|- ( arctan ` ( tan ` ( _pi / 4 ) ) ) = ( arctan ` 1 ) |
3 |
|
pire |
|- _pi e. RR |
4 |
|
4nn |
|- 4 e. NN |
5 |
|
nndivre |
|- ( ( _pi e. RR /\ 4 e. NN ) -> ( _pi / 4 ) e. RR ) |
6 |
3 4 5
|
mp2an |
|- ( _pi / 4 ) e. RR |
7 |
6
|
recni |
|- ( _pi / 4 ) e. CC |
8 |
|
rere |
|- ( ( _pi / 4 ) e. RR -> ( Re ` ( _pi / 4 ) ) = ( _pi / 4 ) ) |
9 |
6 8
|
ax-mp |
|- ( Re ` ( _pi / 4 ) ) = ( _pi / 4 ) |
10 |
|
pirp |
|- _pi e. RR+ |
11 |
|
rphalfcl |
|- ( _pi e. RR+ -> ( _pi / 2 ) e. RR+ ) |
12 |
10 11
|
ax-mp |
|- ( _pi / 2 ) e. RR+ |
13 |
|
rpgt0 |
|- ( ( _pi / 2 ) e. RR+ -> 0 < ( _pi / 2 ) ) |
14 |
12 13
|
ax-mp |
|- 0 < ( _pi / 2 ) |
15 |
|
halfpire |
|- ( _pi / 2 ) e. RR |
16 |
|
lt0neg2 |
|- ( ( _pi / 2 ) e. RR -> ( 0 < ( _pi / 2 ) <-> -u ( _pi / 2 ) < 0 ) ) |
17 |
15 16
|
ax-mp |
|- ( 0 < ( _pi / 2 ) <-> -u ( _pi / 2 ) < 0 ) |
18 |
14 17
|
mpbi |
|- -u ( _pi / 2 ) < 0 |
19 |
|
nnrp |
|- ( 4 e. NN -> 4 e. RR+ ) |
20 |
4 19
|
ax-mp |
|- 4 e. RR+ |
21 |
|
rpdivcl |
|- ( ( _pi e. RR+ /\ 4 e. RR+ ) -> ( _pi / 4 ) e. RR+ ) |
22 |
10 20 21
|
mp2an |
|- ( _pi / 4 ) e. RR+ |
23 |
|
rpgt0 |
|- ( ( _pi / 4 ) e. RR+ -> 0 < ( _pi / 4 ) ) |
24 |
22 23
|
ax-mp |
|- 0 < ( _pi / 4 ) |
25 |
|
neghalfpire |
|- -u ( _pi / 2 ) e. RR |
26 |
|
0re |
|- 0 e. RR |
27 |
25 26 6
|
lttri |
|- ( ( -u ( _pi / 2 ) < 0 /\ 0 < ( _pi / 4 ) ) -> -u ( _pi / 2 ) < ( _pi / 4 ) ) |
28 |
18 24 27
|
mp2an |
|- -u ( _pi / 2 ) < ( _pi / 4 ) |
29 |
3
|
recni |
|- _pi e. CC |
30 |
|
2cnne0 |
|- ( 2 e. CC /\ 2 =/= 0 ) |
31 |
|
divdiv1 |
|- ( ( _pi e. CC /\ ( 2 e. CC /\ 2 =/= 0 ) /\ ( 2 e. CC /\ 2 =/= 0 ) ) -> ( ( _pi / 2 ) / 2 ) = ( _pi / ( 2 x. 2 ) ) ) |
32 |
29 30 30 31
|
mp3an |
|- ( ( _pi / 2 ) / 2 ) = ( _pi / ( 2 x. 2 ) ) |
33 |
|
2t2e4 |
|- ( 2 x. 2 ) = 4 |
34 |
33
|
oveq2i |
|- ( _pi / ( 2 x. 2 ) ) = ( _pi / 4 ) |
35 |
32 34
|
eqtri |
|- ( ( _pi / 2 ) / 2 ) = ( _pi / 4 ) |
36 |
|
rphalflt |
|- ( ( _pi / 2 ) e. RR+ -> ( ( _pi / 2 ) / 2 ) < ( _pi / 2 ) ) |
37 |
12 36
|
ax-mp |
|- ( ( _pi / 2 ) / 2 ) < ( _pi / 2 ) |
38 |
35 37
|
eqbrtrri |
|- ( _pi / 4 ) < ( _pi / 2 ) |
39 |
25
|
rexri |
|- -u ( _pi / 2 ) e. RR* |
40 |
15
|
rexri |
|- ( _pi / 2 ) e. RR* |
41 |
|
elioo2 |
|- ( ( -u ( _pi / 2 ) e. RR* /\ ( _pi / 2 ) e. RR* ) -> ( ( _pi / 4 ) e. ( -u ( _pi / 2 ) (,) ( _pi / 2 ) ) <-> ( ( _pi / 4 ) e. RR /\ -u ( _pi / 2 ) < ( _pi / 4 ) /\ ( _pi / 4 ) < ( _pi / 2 ) ) ) ) |
42 |
39 40 41
|
mp2an |
|- ( ( _pi / 4 ) e. ( -u ( _pi / 2 ) (,) ( _pi / 2 ) ) <-> ( ( _pi / 4 ) e. RR /\ -u ( _pi / 2 ) < ( _pi / 4 ) /\ ( _pi / 4 ) < ( _pi / 2 ) ) ) |
43 |
6 28 38 42
|
mpbir3an |
|- ( _pi / 4 ) e. ( -u ( _pi / 2 ) (,) ( _pi / 2 ) ) |
44 |
9 43
|
eqeltri |
|- ( Re ` ( _pi / 4 ) ) e. ( -u ( _pi / 2 ) (,) ( _pi / 2 ) ) |
45 |
|
atantan |
|- ( ( ( _pi / 4 ) e. CC /\ ( Re ` ( _pi / 4 ) ) e. ( -u ( _pi / 2 ) (,) ( _pi / 2 ) ) ) -> ( arctan ` ( tan ` ( _pi / 4 ) ) ) = ( _pi / 4 ) ) |
46 |
7 44 45
|
mp2an |
|- ( arctan ` ( tan ` ( _pi / 4 ) ) ) = ( _pi / 4 ) |
47 |
2 46
|
eqtr3i |
|- ( arctan ` 1 ) = ( _pi / 4 ) |