English
If f is ContDiffWithinAt ℝ n on s at x, then sinh ∘ f is ContDiffWithinAt ℝ n on s at x.
Русский
Если f имеет ContDiffWithinAt ℝ n на подмножестве s в точке x, то sinh ∘ f имеет ContDiffWithinAt ℝ n на s в точке x.
LaTeX
$$$\operatorname{ContDiffWithinAt}_{\mathbb{R}}^{n}(f, s, x) \Rightarrow \operatorname{ContDiffWithinAt}_{\mathbb{R}}^{n}( \sinh \circ f, s, x ).$$$
Lean4
theorem sinh {n} (hf : ContDiffWithinAt ℝ n f s x) : ContDiffWithinAt ℝ n (fun x => Real.sinh (f x)) s x :=
Real.contDiff_sinh.contDiffAt.comp_contDiffWithinAt x hf