Metamath Proof Explorer


Theorem dpval3

Description: Value of the decimal point construct. (Contributed by Thierry Arnoux, 16-Dec-2021)

Ref Expression
Hypotheses dpval2.a
|- A e. NN0
dpval2.b
|- B e. RR
Assertion dpval3
|- ( A . B ) = _ A B

Proof

Step Hyp Ref Expression
1 dpval2.a
 |-  A e. NN0
2 dpval2.b
 |-  B e. RR
3 1 2 dpval2
 |-  ( A . B ) = ( A + ( B / ; 1 0 ) )
4 df-dp2
 |-  _ A B = ( A + ( B / ; 1 0 ) )
5 3 4 eqtr4i
 |-  ( A . B ) = _ A B