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Metamath Proof Explorer

Theorem ltdiv1

Description: Division of both sides of 'less than' by a positive number. (Contributed by NM, 10-Oct-2004) (Revised by Mario Carneiro, 27-May-2016)

Ref Expression
Assertion ltdiv1 ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 𝐴 < 𝐵 ↔ ( 𝐴 / 𝐶 ) < ( 𝐵 / 𝐶 ) ) )

Proof

Step Hyp Ref Expression
1 simp1 ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐴 ∈ ℝ )
2 simp2 ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐵 ∈ ℝ )
3 simp3l ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐶 ∈ ℝ )
4 simp3r ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 0 < 𝐶 )
5 4 gt0ne0d ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐶 ≠ 0 )
6 3 5 rereccld ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 1 / 𝐶 ) ∈ ℝ )
7 recgt0 ⊢ ( ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) → 0 < ( 1 / 𝐶 ) )
8 7 3ad2ant3 ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 0 < ( 1 / 𝐶 ) )
9 ltmul1 ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( ( 1 / 𝐶 ) ∈ ℝ ∧ 0 < ( 1 / 𝐶 ) ) ) → ( 𝐴 < 𝐵 ↔ ( 𝐴 · ( 1 / 𝐶 ) ) < ( 𝐵 · ( 1 / 𝐶 ) ) ) )
10 1 2 6 8 9 syl112anc ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 𝐴 < 𝐵 ↔ ( 𝐴 · ( 1 / 𝐶 ) ) < ( 𝐵 · ( 1 / 𝐶 ) ) ) )
11 1 recnd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐴 ∈ ℂ )
12 3 recnd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐶 ∈ ℂ )
13 11 12 5 divrecd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 𝐴 / 𝐶 ) = ( 𝐴 · ( 1 / 𝐶 ) ) )
14 2 recnd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → 𝐵 ∈ ℂ )
15 14 12 5 divrecd ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 𝐵 / 𝐶 ) = ( 𝐵 · ( 1 / 𝐶 ) ) )
16 13 15 breq12d ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( ( 𝐴 / 𝐶 ) < ( 𝐵 / 𝐶 ) ↔ ( 𝐴 · ( 1 / 𝐶 ) ) < ( 𝐵 · ( 1 / 𝐶 ) ) ) )
17 10 16 bitr4d ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝐶 ∈ ℝ ∧ 0 < 𝐶 ) ) → ( 𝐴 < 𝐵 ↔ ( 𝐴 / 𝐶 ) < ( 𝐵 / 𝐶 ) ) )