English
The real-valued square root commutes with the natural-coercion from NNReal: (√x as a real) equals √(x as real).
Русский
Корень в ℝ композиционен с отображением из ℝ≥0: (√x) в ℝ равен √(x в ℝ).
LaTeX
$$$ (\\sqrt{x} : \\mathbb{R}) = \\sqrt{(x : \\mathbb{R})}$$$
Lean4
@[simp, norm_cast]
theorem coe_sqrt {x : ℝ≥0} : (NNReal.sqrt x : ℝ) = √(x : ℝ) := by rw [Real.sqrt, Real.toNNReal_coe]