55 secondDeriv f ⟨1, by decide⟩ ⟨1, by decide⟩ x + 56 secondDeriv f ⟨2, by decide⟩ ⟨2, by decide⟩ x + 57 secondDeriv f ⟨3, by decide⟩ ⟨3, by decide⟩ x 58 59/-- Linearity of the directional derivative. -/
used by (10)
From the project-wide theorem graph. These declarations reference this one in their body.