have := @HasDerivAt.comp _ _ _ _ _ _ (fun t => t / c) _ _ _  (l3 (x / c) (by positivity)) (l4 x)
n : ℕ
A a b c d u x✝ y t σ' : ℝ
ψ Ψ : ℝ → ℂ
F G : ℂ → ℂ
f : ℕ → ℂ
𝕜 : Type
inst✝ : _root_.RCLike 𝕜
ha : 0 < a
hb : 0 < b
hc : 0 < c
g : ℝ → ℝ := fun x => a * c / b * (b * (x / c).log).arctan
g₀ : ℝ → ℝ := fun x => if x = 0 then a * c / b * -(π / 2) else g x
g' : ℝ → ℝ := fun x => a * (x / c * (1 + (b * (x / c).log) ^ 2))⁻¹
l3 : ∀ (x : ℝ), 0 < x → HasDerivAt Real.log x⁻¹ x
l4 : ∀ (x : ℝ), HasDerivAt (fun t => t / c) (1 / c) x
x : ℝ
hx : 0 < x
⊢ HasDerivAt (fun t => (t / c).log) x⁻¹ x
n : ℕ
A a b c d u x✝ y t σ' : ℝ
ψ Ψ : ℝ → ℂ
F G : ℂ → ℂ
f : ℕ → ℂ
𝕜 : Type
inst✝ : _root_.RCLike 𝕜
ha : 0 < a
hb : 0 < b
hc : 0 < c
g : ℝ → ℝ := fun x => a * c / b * (b * (x / c).log).arctan
g₀ : ℝ → ℝ := fun x => if x = 0 then a * c / b * -(π / 2) else g x
g' : ℝ → ℝ := fun x => a * (x / c * (1 + (b * (x / c).log) ^ 2))⁻¹
l3 : ∀ (x : ℝ), 0 < x → HasDerivAt Real.log x⁻¹ x
l4 : ∀ (x : ℝ), HasDerivAt (fun t => t / c) (1 / c) x
x : ℝ
hx : 0 < x
this : HasDerivAt (Real.log ∘ fun t => t / c) ((x / c)⁻¹ * (1 / c)) x
⊢ HasDerivAt (fun t => (t / c).log) x⁻¹ x