Metamath Proof Explorer
Description: Addition of positive and nonnegative numbers is positive.
(Contributed by Asger C. Ipsen, 12-May-2021)
|
|
Ref |
Expression |
|
Hypotheses |
leidd.1 |
⊢ ( 𝜑 → 𝐴 ∈ ℝ ) |
|
|
ltnegd.2 |
⊢ ( 𝜑 → 𝐵 ∈ ℝ ) |
|
|
addgtge0d.3 |
⊢ ( 𝜑 → 0 < 𝐴 ) |
|
|
addgtge0d.4 |
⊢ ( 𝜑 → 0 ≤ 𝐵 ) |
|
Assertion |
addgtge0d |
⊢ ( 𝜑 → 0 < ( 𝐴 + 𝐵 ) ) |
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
leidd.1 |
⊢ ( 𝜑 → 𝐴 ∈ ℝ ) |
2 |
|
ltnegd.2 |
⊢ ( 𝜑 → 𝐵 ∈ ℝ ) |
3 |
|
addgtge0d.3 |
⊢ ( 𝜑 → 0 < 𝐴 ) |
4 |
|
addgtge0d.4 |
⊢ ( 𝜑 → 0 ≤ 𝐵 ) |
5 |
|
addgtge0 |
⊢ ( ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) ∧ ( 0 < 𝐴 ∧ 0 ≤ 𝐵 ) ) → 0 < ( 𝐴 + 𝐵 ) ) |
6 |
1 2 3 4 5
|
syl22anc |
⊢ ( 𝜑 → 0 < ( 𝐴 + 𝐵 ) ) |