theorem extracted_formal_statement_7 {m : ℕ+} (x y : EuclideanSpace ℝ (Fin ↑m))
  (h_original_goal : ∑ x_1, y x_1 * x x_1 = x ⬝ᵥ y) : ∑ x_1, y x_1 * x x_1 = ∑ i, x i * y i := sorry

State before:
m : ℕ+
x y : EuclideanSpace ℝ (Fin ↑m)
⊢ ∑ x_1, y x_1 * x x_1 = x ⬝ᵥ y

Tactic: rw [dotProduct]

State after:
[m : ℕ+
 x y : EuclideanSpace ℝ (Fin ↑m)
 ⊢ ∑ x_1, y x_1 * x x_1 = ∑ i, x i * y i]

Relevant lemmas: