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Description: A nonnegative real raised to a nonnegative integer is nonnegative. (Contributed by Mario Carneiro, 28-May-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | reexpcld.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| reexpcld.2 | ⊢ ( 𝜑 → 𝑁 ∈ ℕ0 ) | ||
| expge0d.3 | ⊢ ( 𝜑 → 0 ≤ 𝐴 ) | ||
| Assertion | expge0d | ⊢ ( 𝜑 → 0 ≤ ( 𝐴 ↑ 𝑁 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | reexpcld.1 | ⊢ ( 𝜑 → 𝐴 ∈ ℝ ) | |
| 2 | reexpcld.2 | ⊢ ( 𝜑 → 𝑁 ∈ ℕ0 ) | |
| 3 | expge0d.3 | ⊢ ( 𝜑 → 0 ≤ 𝐴 ) | |
| 4 | expge0 | ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝑁 ∈ ℕ0 ∧ 0 ≤ 𝐴 ) → 0 ≤ ( 𝐴 ↑ 𝑁 ) ) | |
| 5 | 1 2 3 4 | syl3anc | ⊢ ( 𝜑 → 0 ≤ ( 𝐴 ↑ 𝑁 ) ) |