Theorem: deriv.lhopital_zero_right_on_Ico
File: Mathlib/Analysis/Calculus/LHopital.lean

tactic: refine lhopital_zero_right_on_Ioo hab hdf hg' ?_ ?_ hdiv
state_before: a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto (fun x => f x / g x) (𝓝[>] a) l
state_after: case refine_1
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto f (𝓝[>] a) (𝓝 0)

case refine_2
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto g (𝓝[>] a) (𝓝 0)

tactic: rw [← hfa, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
state_before: case refine_1
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto f (𝓝[>] a) (𝓝 0)
state_after: case refine_1
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto f (𝓝[Ioo a b] a) (𝓝 (f a))

tactic: exact ((hcf a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
state_before: case refine_1
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto f (𝓝[Ioo a b] a) (𝓝 (f a))
state_after: no goals

tactic: rw [← hga, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
state_before: case refine_2
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto g (𝓝[>] a) (𝓝 0)
state_after: case refine_2
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto g (𝓝[Ioo a b] a) (𝓝 (g a))

tactic: exact ((hcg a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
state_before: case refine_2
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hcf : ContinuousOn f (Ico a b)
hcg : ContinuousOn g (Ico a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : f a = 0
hga : g a = 0
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
⊢ Tendsto g (𝓝[Ioo a b] a) (𝓝 (g a))
state_after: no goals