∀ {α : Type u_1} [inst : TopologicalSpace α] [inst_1 : MeasurableSpace α] {s : Set α} {f g : α → ℝ}
  {μ : MeasureTheory.Measure α},
  IsConnected s →
    MeasurableSet s →
      ContinuousOn f s →
        MeasureTheory.IntegrableOn g s μ →
          MeasureTheory.IntegrableOn (fun x => f x * g x) s μ →
            (∀ᵐ (x : α) ∂μ.restrict s, 0 ≤ g x) → ∃ c ∈ s, ∫ (x : α) in s, f x * g x ∂μ = f c * ∫ (x : α) in s, g x ∂μ