Step |
Hyp |
Ref |
Expression |
1 |
|
df-ne |
⊢ ( 𝐴 ≠ 0 ↔ ¬ 𝐴 = 0 ) |
2 |
|
ax-rrecex |
⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) → ∃ 𝑥 ∈ ℝ ( 𝐴 · 𝑥 ) = 1 ) |
3 |
|
simpll |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → 𝐴 ∈ ℝ ) |
4 |
3
|
recnd |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → 𝐴 ∈ ℂ ) |
5 |
|
simprl |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → 𝑥 ∈ ℝ ) |
6 |
5
|
recnd |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → 𝑥 ∈ ℂ ) |
7 |
4 6 4
|
mulassd |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( ( 𝐴 · 𝑥 ) · 𝐴 ) = ( 𝐴 · ( 𝑥 · 𝐴 ) ) ) |
8 |
|
simprr |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 𝐴 · 𝑥 ) = 1 ) |
9 |
8
|
oveq1d |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( ( 𝐴 · 𝑥 ) · 𝐴 ) = ( 1 · 𝐴 ) ) |
10 |
3 5 8
|
remulinvcom |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 𝑥 · 𝐴 ) = 1 ) |
11 |
10
|
oveq2d |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 𝐴 · ( 𝑥 · 𝐴 ) ) = ( 𝐴 · 1 ) ) |
12 |
|
ax-1rid |
⊢ ( 𝐴 ∈ ℝ → ( 𝐴 · 1 ) = 𝐴 ) |
13 |
3 12
|
syl |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 𝐴 · 1 ) = 𝐴 ) |
14 |
11 13
|
eqtrd |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 𝐴 · ( 𝑥 · 𝐴 ) ) = 𝐴 ) |
15 |
7 9 14
|
3eqtr3d |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) ∧ ( 𝑥 ∈ ℝ ∧ ( 𝐴 · 𝑥 ) = 1 ) ) → ( 1 · 𝐴 ) = 𝐴 ) |
16 |
2 15
|
rexlimddv |
⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐴 ≠ 0 ) → ( 1 · 𝐴 ) = 𝐴 ) |
17 |
16
|
ex |
⊢ ( 𝐴 ∈ ℝ → ( 𝐴 ≠ 0 → ( 1 · 𝐴 ) = 𝐴 ) ) |
18 |
1 17
|
syl5bir |
⊢ ( 𝐴 ∈ ℝ → ( ¬ 𝐴 = 0 → ( 1 · 𝐴 ) = 𝐴 ) ) |
19 |
|
1re |
⊢ 1 ∈ ℝ |
20 |
|
remul01 |
⊢ ( 1 ∈ ℝ → ( 1 · 0 ) = 0 ) |
21 |
19 20
|
mp1i |
⊢ ( 𝐴 = 0 → ( 1 · 0 ) = 0 ) |
22 |
|
oveq2 |
⊢ ( 𝐴 = 0 → ( 1 · 𝐴 ) = ( 1 · 0 ) ) |
23 |
|
id |
⊢ ( 𝐴 = 0 → 𝐴 = 0 ) |
24 |
21 22 23
|
3eqtr4d |
⊢ ( 𝐴 = 0 → ( 1 · 𝐴 ) = 𝐴 ) |
25 |
18 24
|
pm2.61d2 |
⊢ ( 𝐴 ∈ ℝ → ( 1 · 𝐴 ) = 𝐴 ) |