simp_rw [← tsum_mul_left, ← mul_assoc, mul_comm]
case calc_5
ψ : ℝ → ℝ
diffΨ : ContDiff ℝ 1 ψ
ψpos : ∀ (x : ℝ), 0 ≤ ψ x
suppΨ : support ψ ⊆ Icc (1 / 2) 2
mass_one : ∫ (x : ℝ) in Ioi 0, ψ x / x = 1
X : ℝ
X_pos : 0 < X
ε : ℝ
εpos : 0 < ε
⊢ 1 / (2 * ↑π) *
      ∑' (n : ℕ), ↑(Λ n) * ∫ (t : ℝ), mellin (fun x => ↑(Smooth1 ψ ε x)) (2 + ↑t * I) * (↑X / ↑n) ^ (2 + ↑t * I) =
    ∑' (n : ℕ),
      ↑(Λ n) * (1 / (2 * ↑π) * ∫ (t : ℝ), mellin (fun x => ↑(Smooth1 ψ ε x)) (2 + ↑t * I) * (↑X / ↑n) ^ (2 + ↑t * I))
no goals