Step |
Hyp |
Ref |
Expression |
1 |
|
remulcan2d.1 |
|- ( ph -> A e. RR ) |
2 |
|
remulcan2d.2 |
|- ( ph -> B e. RR ) |
3 |
|
remulcan2d.3 |
|- ( ph -> C e. RR ) |
4 |
|
remulcan2d.4 |
|- ( ph -> C =/= 0 ) |
5 |
|
ax-rrecex |
|- ( ( C e. RR /\ C =/= 0 ) -> E. x e. RR ( C x. x ) = 1 ) |
6 |
3 4 5
|
syl2anc |
|- ( ph -> E. x e. RR ( C x. x ) = 1 ) |
7 |
|
oveq1 |
|- ( ( A x. C ) = ( B x. C ) -> ( ( A x. C ) x. x ) = ( ( B x. C ) x. x ) ) |
8 |
1
|
adantr |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> A e. RR ) |
9 |
8
|
recnd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> A e. CC ) |
10 |
3
|
adantr |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> C e. RR ) |
11 |
10
|
recnd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> C e. CC ) |
12 |
|
simprl |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> x e. RR ) |
13 |
12
|
recnd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> x e. CC ) |
14 |
9 11 13
|
mulassd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( A x. C ) x. x ) = ( A x. ( C x. x ) ) ) |
15 |
|
simprr |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( C x. x ) = 1 ) |
16 |
15
|
oveq2d |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( A x. ( C x. x ) ) = ( A x. 1 ) ) |
17 |
|
ax-1rid |
|- ( A e. RR -> ( A x. 1 ) = A ) |
18 |
8 17
|
syl |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( A x. 1 ) = A ) |
19 |
14 16 18
|
3eqtrd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( A x. C ) x. x ) = A ) |
20 |
2
|
adantr |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> B e. RR ) |
21 |
20
|
recnd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> B e. CC ) |
22 |
21 11 13
|
mulassd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( B x. C ) x. x ) = ( B x. ( C x. x ) ) ) |
23 |
15
|
oveq2d |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( B x. ( C x. x ) ) = ( B x. 1 ) ) |
24 |
|
ax-1rid |
|- ( B e. RR -> ( B x. 1 ) = B ) |
25 |
20 24
|
syl |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( B x. 1 ) = B ) |
26 |
22 23 25
|
3eqtrd |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( B x. C ) x. x ) = B ) |
27 |
19 26
|
eqeq12d |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( ( A x. C ) x. x ) = ( ( B x. C ) x. x ) <-> A = B ) ) |
28 |
7 27
|
syl5ib |
|- ( ( ph /\ ( x e. RR /\ ( C x. x ) = 1 ) ) -> ( ( A x. C ) = ( B x. C ) -> A = B ) ) |
29 |
6 28
|
rexlimddv |
|- ( ph -> ( ( A x. C ) = ( B x. C ) -> A = B ) ) |
30 |
|
oveq1 |
|- ( A = B -> ( A x. C ) = ( B x. C ) ) |
31 |
29 30
|
impbid1 |
|- ( ph -> ( ( A x. C ) = ( B x. C ) <-> A = B ) ) |