exact (differentiableAt_id.const_mul _).smul_const _
𝕜 : Type u_1
E : Type u_2
inst✝³ : NontriviallyNormedField 𝕜
inst✝² : NormedAlgebra 𝕜 ℝ
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace ℝ E
x dx : ℝ
⊢ DifferentiableAt ℝ (fun x => (2 * π * x) • I) x
no goals