Database
REAL AND COMPLEX NUMBERS
Order sets
Infinity and the extended real number system (cont.)
xmulid2
Next ⟩
xmulm1
Metamath Proof Explorer
Ascii
Unicode
Theorem
xmulid2
Description:
Extended real version of
mulid2
.
(Contributed by
Mario Carneiro
, 20-Aug-2015)
Ref
Expression
Assertion
xmulid2
⊢
A
∈
ℝ
*
→
1
⋅
𝑒
A
=
A
Proof
Step
Hyp
Ref
Expression
1
1xr
⊢
1
∈
ℝ
*
2
xmulcom
⊢
1
∈
ℝ
*
∧
A
∈
ℝ
*
→
1
⋅
𝑒
A
=
A
⋅
𝑒
1
3
1
2
mpan
⊢
A
∈
ℝ
*
→
1
⋅
𝑒
A
=
A
⋅
𝑒
1
4
xmulid1
⊢
A
∈
ℝ
*
→
A
⋅
𝑒
1
=
A
5
3
4
eqtrd
⊢
A
∈
ℝ
*
→
1
⋅
𝑒
A
=
A