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Description: The square root of a positive real is a real. (Contributed by Mario Carneiro, 6-Sep-2013)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | sqrtthi.1 | ⊢ 𝐴 ∈ ℝ | |
| sqrpclii.2 | ⊢ 0 < 𝐴 | ||
| Assertion | sqrtpclii | ⊢ ( √ ‘ 𝐴 ) ∈ ℝ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | sqrtthi.1 | ⊢ 𝐴 ∈ ℝ | |
| 2 | sqrpclii.2 | ⊢ 0 < 𝐴 | |
| 3 | 0re | ⊢ 0 ∈ ℝ | |
| 4 | 3 1 2 | ltleii | ⊢ 0 ≤ 𝐴 |
| 5 | 1 | sqrtcli | ⊢ ( 0 ≤ 𝐴 → ( √ ‘ 𝐴 ) ∈ ℝ ) |
| 6 | 4 5 | ax-mp | ⊢ ( √ ‘ 𝐴 ) ∈ ℝ |