∀ {𝕜 : Type u_1} [inst : NontriviallyNormedField 𝕜] {E : Type u_2} [inst_1 : NormedAddCommGroup E]
  [inst_2 : NormedSpace 𝕜 E] {R : Type u_5} [inst_3 : NormedDivisionRing R] [inst_4 : NormedAlgebra 𝕜 R] {h : E → R},
  Differentiable 𝕜 h → (∀ (x : E), h x ≠ 0) → Differentiable 𝕜 h⁻¹ = True