∀ {E : Type u_1} [inst : NormedAddCommGroup E] [inst_1 : NormedSpace ℂ E] {f : E → ℂ} {x : E} {s : Set E},
  DifferentiableWithinAt ℂ f s x →
    UniqueDiffWithinAt ℂ s x →
      fderivWithin ℂ (fun x => Complex.sinh (f x)) s x = Complex.cosh (f x) • fderivWithin ℂ f s x