simp
case h.e'_7
u x : ℝ
l2 : HasDerivAt (fun v => -v * u) (-u) x
⊢ -2 * ↑π * ↑u * I * (e u) x = -u • (2 * ↑π * I * ↑(𝐞 (-x * u)))
case h.e'_7
u x : ℝ
l2 : HasDerivAt (fun v => -v * u) (-u) x
⊢ 2 * ↑π * ↑u * I * ↑(𝐞 (-(x * u))) = ↑u * (2 * ↑π * I * ↑(𝐞 (-(x * u))))