Metamath Proof Explorer


Theorem numsq

Description: Square commutes with canonical numerator. (Contributed by Stefan O'Rear, 15-Sep-2014)

Ref Expression
Assertion numsq ( 𝐴 ∈ ℚ → ( numer ‘ ( 𝐴 ↑ 2 ) ) = ( ( numer ‘ 𝐴 ) ↑ 2 ) )

Proof

Step Hyp Ref Expression
1 numdensq ( 𝐴 ∈ ℚ → ( ( numer ‘ ( 𝐴 ↑ 2 ) ) = ( ( numer ‘ 𝐴 ) ↑ 2 ) ∧ ( denom ‘ ( 𝐴 ↑ 2 ) ) = ( ( denom ‘ 𝐴 ) ↑ 2 ) ) )
2 1 simpld ( 𝐴 ∈ ℚ → ( numer ‘ ( 𝐴 ↑ 2 ) ) = ( ( numer ‘ 𝐴 ) ↑ 2 ) )