theorem extracted_formal_statement_2 {n m : ℕ+} {A : Matrix (Fin ↑m) (Fin ↑n) ℝ} (hA : A = 0)
  (x : EuclideanSpace ℝ (Fin ↑n)) : HasGradientAt (fun x => A *ᵥ x ⬝ᵥ A *ᵥ x) (2 • Aᵀ *ᵥ A *ᵥ x) x := sorry

State before:
case pos
n m : ℕ+
A : Matrix (Fin ↑m) (Fin ↑n) ℝ
hA : A = 0
x : EuclideanSpace ℝ (Fin ↑n)
⊢ HasGradientAt (fun x => A *ᵥ x ⬝ᵥ A *ᵥ x) (2 • Aᵀ *ᵥ A *ᵥ x) x

Tactic: rw [hA]
    simp
    apply hasGradientAt_const

State after:

Relevant lemmas:
hasGradientAt_const : ∀ {𝕜 : Type u_1} {F : Type u_2} [inst : RCLike 𝕜] [inst_1 : NormedAddCommGroup F]
  [inst_2 : InnerProductSpace 𝕜 F] [inst_3 : CompleteSpace F] (x : F) (c : 𝕜), HasGradientAt (fun x => c) 0 x