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Theorem tanadd 12447
Description: Addition formula for tangent. (Contributed by Mario Carneiro, 4-Apr-2015.)
Assertion
Ref Expression
tanadd  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  ( A  +  B
) )  =  ( ( ( tan `  A
)  +  ( tan `  B ) )  / 
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) ) )

Proof of Theorem tanadd
StepHypRef Expression
1 addcl 8819 . . . 4  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( A  +  B
)  e.  CC )
21adantr 451 . . 3  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( A  +  B )  e.  CC )
3 simpr3 963 . . 3  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  ( A  +  B
) )  =/=  0
)
4 tanval 12408 . . 3  |-  ( ( ( A  +  B
)  e.  CC  /\  ( cos `  ( A  +  B ) )  =/=  0 )  -> 
( tan `  ( A  +  B )
)  =  ( ( sin `  ( A  +  B ) )  /  ( cos `  ( A  +  B )
) ) )
52, 3, 4syl2anc 642 . 2  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  ( A  +  B
) )  =  ( ( sin `  ( A  +  B )
)  /  ( cos `  ( A  +  B
) ) ) )
6 sinadd 12444 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( sin `  ( A  +  B )
)  =  ( ( ( sin `  A
)  x.  ( cos `  B ) )  +  ( ( cos `  A
)  x.  ( sin `  B ) ) ) )
76adantr 451 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( sin `  ( A  +  B
) )  =  ( ( ( sin `  A
)  x.  ( cos `  B ) )  +  ( ( cos `  A
)  x.  ( sin `  B ) ) ) )
8 cosadd 12445 . . . . 5  |-  ( ( A  e.  CC  /\  B  e.  CC )  ->  ( cos `  ( A  +  B )
)  =  ( ( ( cos `  A
)  x.  ( cos `  B ) )  -  ( ( sin `  A
)  x.  ( sin `  B ) ) ) )
98adantr 451 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  ( A  +  B
) )  =  ( ( ( cos `  A
)  x.  ( cos `  B ) )  -  ( ( sin `  A
)  x.  ( sin `  B ) ) ) )
107, 9oveq12d 5876 . . 3  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( sin `  ( A  +  B ) )  / 
( cos `  ( A  +  B )
) )  =  ( ( ( ( sin `  A )  x.  ( cos `  B ) )  +  ( ( cos `  A )  x.  ( sin `  B ) ) )  /  ( ( ( cos `  A
)  x.  ( cos `  B ) )  -  ( ( sin `  A
)  x.  ( sin `  B ) ) ) ) )
11 simpll 730 . . . . . . . 8  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  A  e.  CC )
1211coscld 12411 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  A )  e.  CC )
13 simplr 731 . . . . . . . 8  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  B  e.  CC )
1413coscld 12411 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  B )  e.  CC )
1512, 14mulcld 8855 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( cos `  B
) )  e.  CC )
16 simpr1 961 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  A )  =/=  0
)
1711, 16tancld 12412 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  A )  e.  CC )
18 simpr2 962 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( cos `  B )  =/=  0
)
1913, 18tancld 12412 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  B )  e.  CC )
2015, 17, 19adddid 8859 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  +  ( tan `  B ) ) )  =  ( ( ( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  A
) )  +  ( ( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  B
) ) ) )
2112, 14, 17mul32d 9022 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  A
) )  =  ( ( ( cos `  A
)  x.  ( tan `  A ) )  x.  ( cos `  B
) ) )
22 tanval 12408 . . . . . . . . . . 11  |-  ( ( A  e.  CC  /\  ( cos `  A )  =/=  0 )  -> 
( tan `  A
)  =  ( ( sin `  A )  /  ( cos `  A
) ) )
2311, 16, 22syl2anc 642 . . . . . . . . . 10  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  A )  =  ( ( sin `  A
)  /  ( cos `  A ) ) )
2423oveq2d 5874 . . . . . . . . 9  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( tan `  A
) )  =  ( ( cos `  A
)  x.  ( ( sin `  A )  /  ( cos `  A
) ) ) )
2511sincld 12410 . . . . . . . . . 10  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( sin `  A )  e.  CC )
2625, 12, 16divcan2d 9538 . . . . . . . . 9  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( ( sin `  A
)  /  ( cos `  A ) ) )  =  ( sin `  A
) )
2724, 26eqtrd 2315 . . . . . . . 8  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( tan `  A
) )  =  ( sin `  A ) )
2827oveq1d 5873 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( tan `  A ) )  x.  ( cos `  B
) )  =  ( ( sin `  A
)  x.  ( cos `  B ) ) )
2921, 28eqtrd 2315 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  A
) )  =  ( ( sin `  A
)  x.  ( cos `  B ) ) )
3012, 14, 19mulassd 8858 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  B
) )  =  ( ( cos `  A
)  x.  ( ( cos `  B )  x.  ( tan `  B
) ) ) )
31 tanval 12408 . . . . . . . . . . 11  |-  ( ( B  e.  CC  /\  ( cos `  B )  =/=  0 )  -> 
( tan `  B
)  =  ( ( sin `  B )  /  ( cos `  B
) ) )
3213, 18, 31syl2anc 642 . . . . . . . . . 10  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  B )  =  ( ( sin `  B
)  /  ( cos `  B ) ) )
3332oveq2d 5874 . . . . . . . . 9  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  B )  x.  ( tan `  B
) )  =  ( ( cos `  B
)  x.  ( ( sin `  B )  /  ( cos `  B
) ) ) )
3413sincld 12410 . . . . . . . . . 10  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( sin `  B )  e.  CC )
3534, 14, 18divcan2d 9538 . . . . . . . . 9  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  B )  x.  ( ( sin `  B
)  /  ( cos `  B ) ) )  =  ( sin `  B
) )
3633, 35eqtrd 2315 . . . . . . . 8  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  B )  x.  ( tan `  B
) )  =  ( sin `  B ) )
3736oveq2d 5874 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( ( cos `  B
)  x.  ( tan `  B ) ) )  =  ( ( cos `  A )  x.  ( sin `  B ) ) )
3830, 37eqtrd 2315 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  B
) )  =  ( ( cos `  A
)  x.  ( sin `  B ) ) )
3929, 38oveq12d 5876 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  A
) )  +  ( ( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( tan `  B
) ) )  =  ( ( ( sin `  A )  x.  ( cos `  B ) )  +  ( ( cos `  A )  x.  ( sin `  B ) ) ) )
4020, 39eqtrd 2315 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  +  ( tan `  B ) ) )  =  ( ( ( sin `  A )  x.  ( cos `  B
) )  +  ( ( cos `  A
)  x.  ( sin `  B ) ) ) )
41 ax-1cn 8795 . . . . . . 7  |-  1  e.  CC
4241a1i 10 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  1  e.  CC )
4317, 19mulcld 8855 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( tan `  A )  x.  ( tan `  B
) )  e.  CC )
4415, 42, 43subdid 9235 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) )  =  ( ( ( ( cos `  A
)  x.  ( cos `  B ) )  x.  1 )  -  (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  x.  ( tan `  B ) ) ) ) )
4515mulid1d 8852 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  1 )  =  ( ( cos `  A
)  x.  ( cos `  B ) ) )
4612, 14, 17, 19mul4d 9024 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  x.  ( tan `  B ) ) )  =  ( ( ( cos `  A )  x.  ( tan `  A
) )  x.  (
( cos `  B
)  x.  ( tan `  B ) ) ) )
4727, 36oveq12d 5876 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( tan `  A ) )  x.  ( ( cos `  B
)  x.  ( tan `  B ) ) )  =  ( ( sin `  A )  x.  ( sin `  B ) ) )
4846, 47eqtrd 2315 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  x.  ( tan `  B ) ) )  =  ( ( sin `  A )  x.  ( sin `  B ) ) )
4945, 48oveq12d 5876 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  1 )  -  (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  x.  ( tan `  B ) ) ) )  =  ( ( ( cos `  A
)  x.  ( cos `  B ) )  -  ( ( sin `  A
)  x.  ( sin `  B ) ) ) )
5044, 49eqtrd 2315 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( cos `  A
)  x.  ( cos `  B ) )  x.  ( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) )  =  ( ( ( cos `  A
)  x.  ( cos `  B ) )  -  ( ( sin `  A
)  x.  ( sin `  B ) ) ) )
5140, 50oveq12d 5876 . . 3  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  +  ( tan `  B ) ) )  /  ( ( ( cos `  A )  x.  ( cos `  B
) )  x.  (
1  -  ( ( tan `  A )  x.  ( tan `  B
) ) ) ) )  =  ( ( ( ( sin `  A
)  x.  ( cos `  B ) )  +  ( ( cos `  A
)  x.  ( sin `  B ) ) )  /  ( ( ( cos `  A )  x.  ( cos `  B
) )  -  (
( sin `  A
)  x.  ( sin `  B ) ) ) ) )
5217, 19addcld 8854 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( tan `  A )  +  ( tan `  B
) )  e.  CC )
53 subcl 9051 . . . . 5  |-  ( ( 1  e.  CC  /\  ( ( tan `  A
)  x.  ( tan `  B ) )  e.  CC )  ->  (
1  -  ( ( tan `  A )  x.  ( tan `  B
) ) )  e.  CC )
5441, 43, 53sylancr 644 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( 1  -  ( ( tan `  A )  x.  ( tan `  B ) ) )  e.  CC )
55 tanaddlem 12446 . . . . . . . 8  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0 ) )  ->  ( ( cos `  ( A  +  B ) )  =/=  0  <->  ( ( tan `  A )  x.  ( tan `  B ) )  =/=  1 ) )
56553adantr3 1116 . . . . . . 7  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  ( A  +  B ) )  =/=  0  <->  ( ( tan `  A )  x.  ( tan `  B ) )  =/=  1 ) )
573, 56mpbid 201 . . . . . 6  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( tan `  A )  x.  ( tan `  B
) )  =/=  1
)
5857necomd 2529 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  1  =/=  ( ( tan `  A
)  x.  ( tan `  B ) ) )
59 subeq0 9073 . . . . . . 7  |-  ( ( 1  e.  CC  /\  ( ( tan `  A
)  x.  ( tan `  B ) )  e.  CC )  ->  (
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) )  =  0  <->  1  =  ( ( tan `  A
)  x.  ( tan `  B ) ) ) )
6059necon3bid 2481 . . . . . 6  |-  ( ( 1  e.  CC  /\  ( ( tan `  A
)  x.  ( tan `  B ) )  e.  CC )  ->  (
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) )  =/=  0  <->  1  =/=  ( ( tan `  A
)  x.  ( tan `  B ) ) ) )
6141, 43, 60sylancr 644 . . . . 5  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
1  -  ( ( tan `  A )  x.  ( tan `  B
) ) )  =/=  0  <->  1  =/=  (
( tan `  A
)  x.  ( tan `  B ) ) ) )
6258, 61mpbird 223 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( 1  -  ( ( tan `  A )  x.  ( tan `  B ) ) )  =/=  0 )
6312, 14, 16, 18mulne0d 9420 . . . 4  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( ( cos `  A )  x.  ( cos `  B
) )  =/=  0
)
6452, 54, 15, 62, 63divcan5d 9562 . . 3  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( ( cos `  A
)  x.  ( cos `  B ) )  x.  ( ( tan `  A
)  +  ( tan `  B ) ) )  /  ( ( ( cos `  A )  x.  ( cos `  B
) )  x.  (
1  -  ( ( tan `  A )  x.  ( tan `  B
) ) ) ) )  =  ( ( ( tan `  A
)  +  ( tan `  B ) )  / 
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) ) )
6510, 51, 643eqtr2rd 2322 . 2  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( (
( tan `  A
)  +  ( tan `  B ) )  / 
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) )  =  ( ( sin `  ( A  +  B ) )  /  ( cos `  ( A  +  B )
) ) )
665, 65eqtr4d 2318 1  |-  ( ( ( A  e.  CC  /\  B  e.  CC )  /\  ( ( cos `  A )  =/=  0  /\  ( cos `  B
)  =/=  0  /\  ( cos `  ( A  +  B )
)  =/=  0 ) )  ->  ( tan `  ( A  +  B
) )  =  ( ( ( tan `  A
)  +  ( tan `  B ) )  / 
( 1  -  (
( tan `  A
)  x.  ( tan `  B ) ) ) ) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    <-> wb 176    /\ wa 358    /\ w3a 934    = wceq 1623    e. wcel 1684    =/= wne 2446   ` cfv 5255  (class class class)co 5858   CCcc 8735   0cc0 8737   1c1 8738    + caddc 8740    x. cmul 8742    - cmin 9037    / cdiv 9423   sincsin 12345   cosccos 12346   tanctan 12347
This theorem is referenced by:  tanregt0  19901
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1533  ax-5 1544  ax-17 1603  ax-9 1635  ax-8 1643  ax-13 1686  ax-14 1688  ax-6 1703  ax-7 1708  ax-11 1715  ax-12 1866  ax-ext 2264  ax-rep 4131  ax-sep 4141  ax-nul 4149  ax-pow 4188  ax-pr 4214  ax-un 4512  ax-inf2 7342  ax-cnex 8793  ax-resscn 8794  ax-1cn 8795  ax-icn 8796  ax-addcl 8797  ax-addrcl 8798  ax-mulcl 8799  ax-mulrcl 8800  ax-mulcom 8801  ax-addass 8802  ax-mulass 8803  ax-distr 8804  ax-i2m1 8805  ax-1ne0 8806  ax-1rid 8807  ax-rnegex 8808  ax-rrecex 8809  ax-cnre 8810  ax-pre-lttri 8811  ax-pre-lttrn 8812  ax-pre-ltadd 8813  ax-pre-mulgt0 8814  ax-pre-sup 8815  ax-addf 8816  ax-mulf 8817
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935  df-3an 936  df-tru 1310  df-ex 1529  df-nf 1532  df-sb 1630  df-eu 2147  df-mo 2148  df-clab 2270  df-cleq 2276  df-clel 2279  df-nfc 2408  df-ne 2448  df-nel 2449  df-ral 2548  df-rex 2549  df-reu 2550  df-rmo 2551  df-rab 2552  df-v 2790  df-sbc 2992  df-csb 3082  df-dif 3155  df-un 3157  df-in 3159  df-ss 3166  df-pss 3168  df-nul 3456  df-if 3566  df-pw 3627  df-sn 3646  df-pr 3647  df-tp 3648  df-op 3649  df-uni 3828  df-int 3863  df-iun 3907  df-br 4024  df-opab 4078  df-mpt 4079  df-tr 4114  df-eprel 4305  df-id 4309  df-po 4314  df-so 4315  df-fr 4352  df-se 4353  df-we 4354  df-ord 4395  df-on 4396  df-lim 4397  df-suc 4398  df-om 4657  df-xp 4695  df-rel 4696  df-cnv 4697  df-co 4698  df-dm 4699  df-rn 4700  df-res 4701  df-ima 4702  df-iota 5219  df-fun 5257  df-fn 5258  df-f 5259  df-f1 5260  df-fo 5261  df-f1o 5262  df-fv 5263  df-isom 5264  df-ov 5861  df-oprab 5862  df-mpt2 5863  df-1st 6122  df-2nd 6123  df-riota 6304  df-recs 6388  df-rdg 6423  df-1o 6479  df-oadd 6483  df-er 6660  df-pm 6775  df-en 6864  df-dom 6865  df-sdom 6866  df-fin 6867  df-sup 7194  df-oi 7225  df-card 7572  df-pnf 8869  df-mnf 8870  df-xr 8871  df-ltxr 8872  df-le 8873  df-sub 9039  df-neg 9040  df-div 9424  df-nn 9747  df-2 9804  df-3 9805  df-n0 9966  df-z 10025  df-uz 10231  df-rp 10355  df-ico 10662  df-fz 10783  df-fzo 10871  df-fl 10925  df-seq 11047  df-exp 11105  df-fac 11289  df-bc 11316  df-hash 11338  df-shft 11562  df-cj 11584  df-re 11585  df-im 11586  df-sqr 11720  df-abs 11721  df-limsup 11945  df-clim 11962  df-rlim 11963  df-sum 12159  df-ef 12349  df-sin 12351  df-cos 12352  df-tan 12353
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