Metamath Proof Explorer


Theorem sn-rediv1d

Description: A number divided by 1 is itself. (Contributed by SN, 2-Apr-2026)

Ref Expression
Hypothesis sn-rediv1d.a
|- ( ph -> A e. RR )
Assertion sn-rediv1d
|- ( ph -> ( A /R 1 ) = A )

Proof

Step Hyp Ref Expression
1 sn-rediv1d.a
 |-  ( ph -> A e. RR )
2 remullid
 |-  ( A e. RR -> ( 1 x. A ) = A )
3 1 2 syl
 |-  ( ph -> ( 1 x. A ) = A )
4 1red
 |-  ( ph -> 1 e. RR )
5 ax-1ne0
 |-  1 =/= 0
6 5 a1i
 |-  ( ph -> 1 =/= 0 )
7 1 1 4 6 redivmuld
 |-  ( ph -> ( ( A /R 1 ) = A <-> ( 1 x. A ) = A ) )
8 3 7 mpbird
 |-  ( ph -> ( A /R 1 ) = A )