Metamath Proof Explorer


Theorem divid

Description: A number divided by itself is one. (Contributed by NM, 1-Aug-2004)

Ref Expression
Assertion divid
|- ( ( A e. CC /\ A =/= 0 ) -> ( A / A ) = 1 )

Proof

Step Hyp Ref Expression
1 divrec
 |-  ( ( A e. CC /\ A e. CC /\ A =/= 0 ) -> ( A / A ) = ( A x. ( 1 / A ) ) )
2 1 3anidm12
 |-  ( ( A e. CC /\ A =/= 0 ) -> ( A / A ) = ( A x. ( 1 / A ) ) )
3 recid
 |-  ( ( A e. CC /\ A =/= 0 ) -> ( A x. ( 1 / A ) ) = 1 )
4 2 3 eqtrd
 |-  ( ( A e. CC /\ A =/= 0 ) -> ( A / A ) = 1 )