Theorem: MeasureTheory.integral_Iic_deriv_mul_eq_sub
File: Mathlib/MeasureTheory/Integral/IntegralEqImproper.lean

Proof steps:
state_before: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[<] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
state_after: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
tactic: rw [← Iic_diff_right] at h_zero
state_before: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
state_after: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
tactic: let f := Function.update (u * v) a a'
state_before: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
state_after: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
hderiv : ∀ x ∈ Iio a, HasDerivAt f (u' x * v x + u x * v' x) x
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
tactic: have hderiv : ∀ x ∈ Iio a, HasDerivAt f (u' x * v x + u x * v' x) x := by
    intro x hx
    apply ((hu x hx).mul (hv x hx)).congr_of_eventuallyEq
    filter_upwards [Iio_mem_nhds hx] with x (hx : x < a)
    exact Function.update_noteq (ne_of_lt hx) a' (u * v)
state_before: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
hderiv : ∀ x ∈ Iio a, HasDerivAt f (u' x * v x + u x * v' x) x
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
state_after: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
hderiv : ∀ x ∈ Iio a, HasDerivAt f (u' x * v x + u x * v' x) x
htendsto : Tendsto f atBot (𝓝 b')
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
tactic: have htendsto : Tendsto f atBot (𝓝 b') := by
    apply h_infty.congr'
    filter_upwards [Iio_mem_atBot a] with x (hx : x < a)
    exact (Function.update_noteq (ne_of_lt hx) a' (u * v)).symm
state_before: A : Type u_1
inst✝² : NormedRing A
inst✝¹ : NormedAlgebra ℝ A
a b : ℝ
a' b' : A
u v u' v' : ℝ → A
inst✝ : CompleteSpace A
hu : ∀ x ∈ Iio a, HasDerivAt u (u' x) x
hv : ∀ x ∈ Iio a, HasDerivAt v (v' x) x
huv : IntegrableOn (u' * v + u * v') (Iic a) volume
h_zero : Tendsto (u * v) (𝓝[Iic a \ {a}] a) (𝓝 a')
h_infty : Tendsto (u * v) atBot (𝓝 b')
f : ℝ → A := Function.update (u * v) a a'
hderiv : ∀ x ∈ Iio a, HasDerivAt f (u' x * v x + u x * v' x) x
htendsto : Tendsto f atBot (𝓝 b')
⊢ ∫ (x : ℝ) in Iic a, u' x * v x + u x * v' x = a' - b'
state_after: no goals
tactic: simpa using integral_Iic_of_hasDerivAt_of_tendsto
    (continuousWithinAt_update_same.mpr h_zero) hderiv huv htendsto