l3lab/ntp-mathlib huggingface dataset:
theorem lhopital_zero_atBot_on_Iio (hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x)
    (hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x) (hg' : ∀ x ∈ Iio a, g' x ≠ 0)
    (hfbot : Tendsto f atBot (𝓝 0)) (hgbot : Tendsto g atBot (𝓝 0))
    (hdiv : Tendsto (fun x => f' x / g' x) atBot l) : Tendsto (fun x => f x / g x) atBot l := by
  -- Here, we essentially compose by `Neg.neg`. The following is mostly technical details.
  have hdnf : ∀ x ∈ -Iio a, HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x := fun x hx =>
    comp x (hff' (-x) hx) (hasDerivAt_neg x)
  have hdng : ∀ x ∈ -Iio a, HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x := fun x hx =>
    comp x (hgg' (-x) hx) (hasDerivAt_neg x)
  rw [preimage_neg_Iio] at hdnf
  rw [preimage_neg_Iio] at hdng
  have := lhopital_zero_atTop_on_Ioi hdnf hdng
    (by
      intro x hx h
      apply hg' _ (by rw [← preimage_neg_Iio] at hx; exact hx)
      rwa [mul_comm, ← neg_eq_neg_one_mul, neg_eq_zero] at h)
    (hfbot.comp tendsto_neg_atTop_atBot) (hgbot.comp tendsto_neg_atTop_atBot)
    (by
      

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x
hg' : ∀ x ∈ Iio a, g' x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => f' x / g' x) atBot l
hdnf : ∀ x ∈ Ioi (-a), HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x
hdng : ∀ x ∈ Ioi (-a), HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x
⊢ Tendsto (fun x => f' (-x) * -1 / (g' (-x) * -1)) atTop ?m.32231

Next tactic:
simp only [mul_one, mul_neg, neg_div_neg_eq]
theorem lhopital_zero_atBot_on_Iio (hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x)
    (hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x) (hg' : ∀ x ∈ Iio a, g' x ≠ 0)
    (hfbot : Tendsto f atBot (𝓝 0)) (hgbot : Tendsto g atBot (𝓝 0))
    (hdiv : Tendsto (fun x => f' x / g' x) atBot l) : Tendsto (fun x => f x / g x) atBot l := by
  -- Here, we essentially compose by `Neg.neg`. The following is mostly technical details.
  have hdnf : ∀ x ∈ -Iio a, HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x := fun x hx =>
    comp x (hff' (-x) hx) (hasDerivAt_neg x)
  have hdng : ∀ x ∈ -Iio a, HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x := fun x hx =>
    comp x (hgg' (-x) hx) (hasDerivAt_neg x)
  rw [preimage_neg_Iio] at hdnf
  rw [preimage_neg_Iio] at hdng
  have := lhopital_zero_atTop_on_Ioi hdnf hdng
    (by
      intro x hx h
      apply hg' _ (by rw [← preimage_neg_Iio] at hx; exact hx)
      rwa [mul_comm, ← neg_eq_neg_one_mul, neg_eq_zero] at h)
    (hfbot.comp tendsto_neg_atTop_atBot) (hgbot.comp tendsto_neg_atTop_atBot)
    (by
      simp only [mul_one, mul_neg, neg_div_neg_eq]
      

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x
hg' : ∀ x ∈ Iio a, g' x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => f' x / g' x) atBot l
hdnf : ∀ x ∈ Ioi (-a), HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x
hdng : ∀ x ∈ Ioi (-a), HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x
⊢ Tendsto (fun x => f' (-x) / g' (-x)) atTop ?m.32231

Next tactic:
exact (tendsto_congr fun x => rfl).mp (hdiv.comp tendsto_neg_atTop_atBot)
theorem lhopital_zero_atBot_on_Iio (hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x)
    (hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x) (hg' : ∀ x ∈ Iio a, g' x ≠ 0)
    (hfbot : Tendsto f atBot (𝓝 0)) (hgbot : Tendsto g atBot (𝓝 0))
    (hdiv : Tendsto (fun x => f' x / g' x) atBot l) : Tendsto (fun x => f x / g x) atBot l := by
  -- Here, we essentially compose by `Neg.neg`. The following is mostly technical details.
  have hdnf : ∀ x ∈ -Iio a, HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x := fun x hx =>
    comp x (hff' (-x) hx) (hasDerivAt_neg x)
  have hdng : ∀ x ∈ -Iio a, HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x := fun x hx =>
    comp x (hgg' (-x) hx) (hasDerivAt_neg x)
  rw [preimage_neg_Iio] at hdnf
  rw [preimage_neg_Iio] at hdng
  have := lhopital_zero_atTop_on_Ioi hdnf hdng
    (by
      intro x hx h
      apply hg' _ (by rw [← preimage_neg_Iio] at hx; exact hx)
      rwa [mul_comm, ← neg_eq_neg_one_mul, neg_eq_zero] at h)
    (hfbot.comp tendsto_neg_atTop_atBot) (hgbot.comp tendsto_neg_atTop_atBot)
    (by
      simp only [mul_one, mul_neg, neg_div_neg_eq]
      exact (tendsto_congr fun x => rfl).mp (hdiv.comp tendsto_neg_atTop_atBot))
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x
hg' : ∀ x ∈ Iio a, g' x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => f' x / g' x) atBot l
hdnf : ∀ x ∈ Ioi (-a), HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x
hdng : ∀ x ∈ Ioi (-a), HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x
this : Tendsto (fun x => (f ∘ Neg.neg) x / (g ∘ Neg.neg) x) atTop l
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
have := this.comp tendsto_neg_atBot_atTop
theorem lhopital_zero_atBot_on_Iio (hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x)
    (hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x) (hg' : ∀ x ∈ Iio a, g' x ≠ 0)
    (hfbot : Tendsto f atBot (𝓝 0)) (hgbot : Tendsto g atBot (𝓝 0))
    (hdiv : Tendsto (fun x => f' x / g' x) atBot l) : Tendsto (fun x => f x / g x) atBot l := by
  -- Here, we essentially compose by `Neg.neg`. The following is mostly technical details.
  have hdnf : ∀ x ∈ -Iio a, HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x := fun x hx =>
    comp x (hff' (-x) hx) (hasDerivAt_neg x)
  have hdng : ∀ x ∈ -Iio a, HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x := fun x hx =>
    comp x (hgg' (-x) hx) (hasDerivAt_neg x)
  rw [preimage_neg_Iio] at hdnf
  rw [preimage_neg_Iio] at hdng
  have := lhopital_zero_atTop_on_Ioi hdnf hdng
    (by
      intro x hx h
      apply hg' _ (by rw [← preimage_neg_Iio] at hx; exact hx)
      rwa [mul_comm, ← neg_eq_neg_one_mul, neg_eq_zero] at h)
    (hfbot.comp tendsto_neg_atTop_atBot) (hgbot.comp tendsto_neg_atTop_atBot)
    (by
      simp only [mul_one, mul_neg, neg_div_neg_eq]
      exact (tendsto_congr fun x => rfl).mp (hdiv.comp tendsto_neg_atTop_atBot))
  have := this.comp tendsto_neg_atBot_atTop
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x
hg' : ∀ x ∈ Iio a, g' x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => f' x / g' x) atBot l
hdnf : ∀ x ∈ Ioi (-a), HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x
hdng : ∀ x ∈ Ioi (-a), HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x
this✝ : Tendsto (fun x => (f ∘ Neg.neg) x / (g ∘ Neg.neg) x) atTop l
this : Tendsto ((fun x => (f ∘ Neg.neg) x / (g ∘ Neg.neg) x) ∘ Neg.neg) atBot l
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
unfold Function.comp at this
theorem lhopital_zero_atBot_on_Iio (hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x)
    (hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x) (hg' : ∀ x ∈ Iio a, g' x ≠ 0)
    (hfbot : Tendsto f atBot (𝓝 0)) (hgbot : Tendsto g atBot (𝓝 0))
    (hdiv : Tendsto (fun x => f' x / g' x) atBot l) : Tendsto (fun x => f x / g x) atBot l := by
  -- Here, we essentially compose by `Neg.neg`. The following is mostly technical details.
  have hdnf : ∀ x ∈ -Iio a, HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x := fun x hx =>
    comp x (hff' (-x) hx) (hasDerivAt_neg x)
  have hdng : ∀ x ∈ -Iio a, HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x := fun x hx =>
    comp x (hgg' (-x) hx) (hasDerivAt_neg x)
  rw [preimage_neg_Iio] at hdnf
  rw [preimage_neg_Iio] at hdng
  have := lhopital_zero_atTop_on_Ioi hdnf hdng
    (by
      intro x hx h
      apply hg' _ (by rw [← preimage_neg_Iio] at hx; exact hx)
      rwa [mul_comm, ← neg_eq_neg_one_mul, neg_eq_zero] at h)
    (hfbot.comp tendsto_neg_atTop_atBot) (hgbot.comp tendsto_neg_atTop_atBot)
    (by
      simp only [mul_one, mul_neg, neg_div_neg_eq]
      exact (tendsto_congr fun x => rfl).mp (hdiv.comp tendsto_neg_atTop_atBot))
  have := this.comp tendsto_neg_atBot_atTop
  unfold Function.comp at this
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hff' : ∀ x ∈ Iio a, HasDerivAt f (f' x) x
hgg' : ∀ x ∈ Iio a, HasDerivAt g (g' x) x
hg' : ∀ x ∈ Iio a, g' x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => f' x / g' x) atBot l
hdnf : ∀ x ∈ Ioi (-a), HasDerivAt (f ∘ Neg.neg) (f' (-x) * -1) x
hdng : ∀ x ∈ Ioi (-a), HasDerivAt (g ∘ Neg.neg) (g' (-x) * -1) x
this✝ : Tendsto (fun x => (f ∘ Neg.neg) x / (g ∘ Neg.neg) x) atTop l
this : Tendsto (fun x => (fun x => f (-x) / g (-x)) (-x)) atBot l
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
simpa only [neg_neg]
theorem lhopital_zero_right_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0) (hfa : Tendsto f (𝓝[>] a) (𝓝 0))
    (hga : Tendsto g (𝓝[>] a) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[>] a) l) :
    Tendsto (fun x => f x / g x) (𝓝[>] a) l := by
  

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

Next tactic:
have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
theorem lhopital_zero_right_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0) (hfa : Tendsto f (𝓝[>] a) (𝓝 0))
    (hga : Tendsto g (𝓝[>] a) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[>] a) l) :
    Tendsto (fun x => f x / g x) (𝓝[>] a) l := by
  have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioo a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : Tendsto f (𝓝[>] a) (𝓝 0)
hga : Tendsto g (𝓝[>] a) (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x
⊢ Tendsto (fun x => f x / g x) (𝓝[>] a) l

Next tactic:
have hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
theorem lhopital_zero_right_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0) (hfa : Tendsto f (𝓝[>] a) (𝓝 0))
    (hga : Tendsto g (𝓝[>] a) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[>] a) l) :
    Tendsto (fun x => f x / g x) (𝓝[>] a) l := by
  have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
  have hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioo a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfa : Tendsto f (𝓝[>] a) (𝓝 0)
hga : Tendsto g (𝓝[>] a) (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[>] a) l
hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x
hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x
⊢ Tendsto (fun x => f x / g x) (𝓝[>] a) l

Next tactic:
exact HasDerivAt.lhopital_zero_right_on_Ioo hab (fun x hx => (hdf x hx).hasDerivAt)
    (fun x hx => (hdg x hx).hasDerivAt) hg' hfa hga hdiv
theorem lhopital_zero_right_on_Ico (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 := by
  

Proof state:
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

Next tactic:
refine' lhopital_zero_right_on_Ioo hab hdf hg' _ _ hdiv
theorem lhopital_zero_right_on_Ico (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 := by
  refine' lhopital_zero_right_on_Ioo hab hdf hg' _ _ hdiv
  · 

Proof state:
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 (fun x => f x) (𝓝[>] a) (𝓝 0)

Next tactic:
rw [← hfa, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
theorem lhopital_zero_right_on_Ico (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 := by
  refine' lhopital_zero_right_on_Ioo hab hdf hg' _ _ hdiv
  · rw [← hfa, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
    

Proof state:
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 (fun x => f x) (𝓝[Ioo a b] a) (𝓝 (f a))

Next tactic:
exact ((hcf a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
theorem lhopital_zero_right_on_Ico (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 := by
  refine' lhopital_zero_right_on_Ioo hab hdf hg' _ _ hdiv
  · rw [← hfa, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
    exact ((hcf a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
  · 

Proof state:
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 (fun x => g x) (𝓝[>] a) (𝓝 0)

Next tactic:
rw [← hga, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
theorem lhopital_zero_right_on_Ico (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 := by
  refine' lhopital_zero_right_on_Ioo hab hdf hg' _ _ hdiv
  · rw [← hfa, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
    exact ((hcf a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
  · rw [← hga, ← nhdsWithin_Ioo_eq_nhdsWithin_Ioi hab]
    

Proof state:
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 (fun x => g x) (𝓝[Ioo a b] a) (𝓝 (g a))

Next tactic:
exact ((hcg a <| left_mem_Ico.mpr hab).mono Ioo_subset_Ico_self).tendsto
theorem lhopital_zero_left_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, (deriv g) x ≠ 0) (hfb : Tendsto f (𝓝[<] b) (𝓝 0))
    (hgb : Tendsto g (𝓝[<] b) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[<] b) l) :
    Tendsto (fun x => f x / g x) (𝓝[<] b) l := by
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioo a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfb : Tendsto f (𝓝[<] b) (𝓝 0)
hgb : Tendsto g (𝓝[<] b) (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[<] b) l
⊢ Tendsto (fun x => f x / g x) (𝓝[<] b) l

Next tactic:
have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
theorem lhopital_zero_left_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, (deriv g) x ≠ 0) (hfb : Tendsto f (𝓝[<] b) (𝓝 0))
    (hgb : Tendsto g (𝓝[<] b) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[<] b) l) :
    Tendsto (fun x => f x / g x) (𝓝[<] b) l := by
  have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioo a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfb : Tendsto f (𝓝[<] b) (𝓝 0)
hgb : Tendsto g (𝓝[<] b) (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[<] b) l
hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x
⊢ Tendsto (fun x => f x / g x) (𝓝[<] b) l

Next tactic:
have hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
theorem lhopital_zero_left_on_Ioo (hdf : DifferentiableOn ℝ f (Ioo a b))
    (hg' : ∀ x ∈ Ioo a b, (deriv g) x ≠ 0) (hfb : Tendsto f (𝓝[<] b) (𝓝 0))
    (hgb : Tendsto g (𝓝[<] b) (𝓝 0))
    (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) (𝓝[<] b) l) :
    Tendsto (fun x => f x / g x) (𝓝[<] b) l := by
  have hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioo_mem_nhds hx.1 hx.2)
  have hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioo a b)
hg' : ∀ x ∈ Ioo a b, deriv g x ≠ 0
hfb : Tendsto f (𝓝[<] b) (𝓝 0)
hgb : Tendsto g (𝓝[<] b) (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) (𝓝[<] b) l
hdf : ∀ x ∈ Ioo a b, DifferentiableAt ℝ f x
hdg : ∀ x ∈ Ioo a b, DifferentiableAt ℝ g x
⊢ Tendsto (fun x => f x / g x) (𝓝[<] b) l

Next tactic:
exact HasDerivAt.lhopital_zero_left_on_Ioo hab (fun x hx => (hdf x hx).hasDerivAt)
    (fun x hx => (hdg x hx).hasDerivAt) hg' hfb hgb hdiv
theorem lhopital_zero_atTop_on_Ioi (hdf : DifferentiableOn ℝ f (Ioi a))
    (hg' : ∀ x ∈ Ioi a, (deriv g) x ≠ 0) (hftop : Tendsto f atTop (𝓝 0))
    (hgtop : Tendsto g atTop (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atTop l) :
    Tendsto (fun x => f x / g x) atTop l := by
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Ioi a)
hg' : ∀ x ∈ Ioi a, deriv g x ≠ 0
hftop : Tendsto f atTop (𝓝 0)
hgtop : Tendsto g atTop (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atTop l
⊢ Tendsto (fun x => f x / g x) atTop l

Next tactic:
have hdf : ∀ x ∈ Ioi a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioi_mem_nhds hx)
theorem lhopital_zero_atTop_on_Ioi (hdf : DifferentiableOn ℝ f (Ioi a))
    (hg' : ∀ x ∈ Ioi a, (deriv g) x ≠ 0) (hftop : Tendsto f atTop (𝓝 0))
    (hgtop : Tendsto g atTop (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atTop l) :
    Tendsto (fun x => f x / g x) atTop l := by
  have hdf : ∀ x ∈ Ioi a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioi_mem_nhds hx)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioi a)
hg' : ∀ x ∈ Ioi a, deriv g x ≠ 0
hftop : Tendsto f atTop (𝓝 0)
hgtop : Tendsto g atTop (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atTop l
hdf : ∀ x ∈ Ioi a, DifferentiableAt ℝ f x
⊢ Tendsto (fun x => f x / g x) atTop l

Next tactic:
have hdg : ∀ x ∈ Ioi a, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
theorem lhopital_zero_atTop_on_Ioi (hdf : DifferentiableOn ℝ f (Ioi a))
    (hg' : ∀ x ∈ Ioi a, (deriv g) x ≠ 0) (hftop : Tendsto f atTop (𝓝 0))
    (hgtop : Tendsto g atTop (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atTop l) :
    Tendsto (fun x => f x / g x) atTop l := by
  have hdf : ∀ x ∈ Ioi a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Ioi_mem_nhds hx)
  have hdg : ∀ x ∈ Ioi a, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Ioi a)
hg' : ∀ x ∈ Ioi a, deriv g x ≠ 0
hftop : Tendsto f atTop (𝓝 0)
hgtop : Tendsto g atTop (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atTop l
hdf : ∀ x ∈ Ioi a, DifferentiableAt ℝ f x
hdg : ∀ x ∈ Ioi a, DifferentiableAt ℝ g x
⊢ Tendsto (fun x => f x / g x) atTop l

Next tactic:
exact HasDerivAt.lhopital_zero_atTop_on_Ioi (fun x hx => (hdf x hx).hasDerivAt)
    (fun x hx => (hdg x hx).hasDerivAt) hg' hftop hgtop hdiv
theorem lhopital_zero_atBot_on_Iio (hdf : DifferentiableOn ℝ f (Iio a))
    (hg' : ∀ x ∈ Iio a, (deriv g) x ≠ 0) (hfbot : Tendsto f atBot (𝓝 0))
    (hgbot : Tendsto g atBot (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atBot l) :
    Tendsto (fun x => f x / g x) atBot l := by
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf : DifferentiableOn ℝ f (Iio a)
hg' : ∀ x ∈ Iio a, deriv g x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atBot l
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
have hdf : ∀ x ∈ Iio a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Iio_mem_nhds hx)
theorem lhopital_zero_atBot_on_Iio (hdf : DifferentiableOn ℝ f (Iio a))
    (hg' : ∀ x ∈ Iio a, (deriv g) x ≠ 0) (hfbot : Tendsto f atBot (𝓝 0))
    (hgbot : Tendsto g atBot (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atBot l) :
    Tendsto (fun x => f x / g x) atBot l := by
  have hdf : ∀ x ∈ Iio a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Iio_mem_nhds hx)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Iio a)
hg' : ∀ x ∈ Iio a, deriv g x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atBot l
hdf : ∀ x ∈ Iio a, DifferentiableAt ℝ f x
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
have hdg : ∀ x ∈ Iio a, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
theorem lhopital_zero_atBot_on_Iio (hdf : DifferentiableOn ℝ f (Iio a))
    (hg' : ∀ x ∈ Iio a, (deriv g) x ≠ 0) (hfbot : Tendsto f atBot (𝓝 0))
    (hgbot : Tendsto g atBot (𝓝 0)) (hdiv : Tendsto (fun x => (deriv f) x / (deriv g) x) atBot l) :
    Tendsto (fun x => f x / g x) atBot l := by
  have hdf : ∀ x ∈ Iio a, DifferentiableAt ℝ f x := fun x hx =>
    (hdf x hx).differentiableAt (Iio_mem_nhds hx)
  have hdg : ∀ x ∈ Iio a, DifferentiableAt ℝ g x := fun x hx =>
    by_contradiction fun h => hg' x hx (deriv_zero_of_not_differentiableAt h)
  

Proof state:
a b : ℝ
hab : a < b
l : Filter ℝ
f f' g g' : ℝ → ℝ
hdf✝ : DifferentiableOn ℝ f (Iio a)
hg' : ∀ x ∈ Iio a, deriv g x ≠ 0
hfbot : Tendsto f atBot (𝓝 0)
hgbot : Tendsto g atBot (𝓝 0)
hdiv : Tendsto (fun x => deriv f x / deriv g x) atBot l
hdf : ∀ x ∈ Iio a, DifferentiableAt ℝ f x
hdg : ∀ x ∈ Iio a, DifferentiableAt ℝ g x
⊢ Tendsto (fun x => f x / g x) atBot l

Next tactic:
exact HasDerivAt.lhopital_zero_atBot_on_Iio (fun x hx => (hdf x hx).hasDerivAt)
    (fun x hx => (hdg x hx).hasDerivAt) hg' hfbot hgbot hdiv