𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
a b : 𝕜
s : Set 𝕜
h : b ≠ a
hc : ContinuousWithinAt f s b
⊢ ContinuousWithinAt (dslope f a) s b
𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
a b : 𝕜
s : Set 𝕜
h : b ≠ a
⊢ ContinuousWithinAt (dslope f a) s b ↔ ContinuousWithinAt f s b
refine' ⟨ContinuousWithinAt.of_dslope, fun hc => _⟩
𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
a b : 𝕜
s : Set 𝕜
h : b ≠ a
hc : ContinuousWithinAt f s b
⊢ ContinuousWithinAt (slope f a) s b
𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
a b : 𝕜
s : Set 𝕜
h : b ≠ a
hc : ContinuousWithinAt f s b
⊢ ContinuousWithinAt (dslope f a) s b
simp only [dslope, continuousWithinAt_update_of_ne h]
no goals
𝕜 : Type u_1
E : Type u_2
inst✝² : NontriviallyNormedField 𝕜
inst✝¹ : NormedAddCommGroup E
inst✝ : NormedSpace 𝕜 E
f : 𝕜 → E
a b : 𝕜
s : Set 𝕜
h : b ≠ a
hc : ContinuousWithinAt f s b
⊢ ContinuousWithinAt (slope f a) s b
exact ((continuousWithinAt_id.sub continuousWithinAt_const).inv₀ (sub_ne_zero.2 h)).smul
  (hc.sub continuousWithinAt_const)