English
If h : HasLineDerivAt 𝕜 f f' x v, then for any scalar c, HasLineDerivAt 𝕜 f (c • f') x (c • v).
Русский
Если h : HasLineDerivAt 𝕜 f f' x v, то для любого скаляра c имеет место HasLineDerivAt 𝕜 f (c • f') x (c • v).
LaTeX
$$$$ HasLineDerivAt 𝕜 f f' x v \Rightarrow HasLineDerivAt 𝕜 f (c \cdot f') x (c \cdot v) $$$$
Lean4
theorem smul (h : HasLineDerivAt 𝕜 f f' x v) (c : 𝕜) : HasLineDerivAt 𝕜 f (c • f') x (c • v) :=
by
simp only [← hasLineDerivWithinAt_univ] at h ⊢
exact HasLineDerivWithinAt.smul h c