Description: The square root of a positive real is positive. (Contributed by Mario Carneiro, 29-May-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | sqrgt0d.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ+ ) | |
| Assertion | rpsqrtcld | ⊢ ( 𝜑 → ( √ ‘ 𝐴 ) ∈ ℝ+ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sqrgt0d.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ+ ) | |
| 2 | rpsqrtcl | ⊢ ( 𝐴 ∈ ℝ+ → ( √ ‘ 𝐴 ) ∈ ℝ+ ) | |
| 3 | 1 2 | syl | ⊢ ( 𝜑 → ( √ ‘ 𝐴 ) ∈ ℝ+ ) |