mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Projection

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝¹ : Oriented ℝ V (Fin 2)
p p' : P
s : AffineSubspace ℝ P
inst✝ : s.direction.HasOrthogonalProjection
hp : p ∉ s
h : p' ∈ s
hp' : p' ≠ ↑((orthogonalProjection s) p)
⊢ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(π / 2) ∨ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(-π / 2)

Tactic:
have : Nonempty s := ⟨p', h⟩

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝¹ : Oriented ℝ V (Fin 2)
p p' : P
s : AffineSubspace ℝ P
inst✝ : s.direction.HasOrthogonalProjection
hp : p ∉ s
h : p' ∈ s
hp' : p' ≠ ↑((orthogonalProjection s) p)
this : Nonempty ↥s
⊢ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(π / 2) ∨ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(-π / 2)
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Affine

Goal state before:
pp: case pos
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p₁ p₂ p₃ p₄ p₅ : P
hp₁p₂ : p₁ ≠ p₂
hp₃p₄ : p₃ ≠ p₄
hc : Collinear ℝ {p₁, p₂, p₃, p₄}
hr : SameRay ℝ (p₂ -ᵥ p₁) (p₄ -ᵥ p₃)
hc₅₁₂ : Collinear ℝ {p₅, p₁, p₂}
⊢ (∡ p₁ p₅ p₂).sign = (∡ p₃ p₅ p₄).sign

pp: case neg
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p₁ p₂ p₃ p₄ p₅ : P
hp₁p₂ : p₁ ≠ p₂
hp₃p₄ : p₃ ≠ p₄
hc : Collinear ℝ {p₁, p₂, p₃, p₄}
hr : SameRay ℝ (p₂ -ᵥ p₁) (p₄ -ᵥ p₃)
hc₅₁₂ : ¬Collinear ℝ {p₅, p₁, p₂}
⊢ (∡ p₁ p₅ p₂).sign = (∡ p₃ p₅ p₄).sign

Tactic:
· have hc₅₁₂₃₄ : Collinear ℝ ({p₅, p₁, p₂, p₃, p₄} : Set P) :=
      (hc.collinear_insert_iff_of_ne (Set.mem_insert _ _)
        (Set.mem_insert_of_mem _ (Set.mem_insert _ _)) hp₁p₂).2 hc₅₁₂
    have hc₅₃₄ : Collinear ℝ ({p₅, p₃, p₄} : Set P) :=
      (hc.collinear_insert_iff_of_ne
        (Set.mem_insert_of_mem _ (Set.mem_insert_of_mem _ (Set.mem_insert _ _)))
        (Set.mem_insert_of_mem _ (Set.mem_insert_of_mem _ (Set.mem_insert_of_mem _
          (Set.mem_singleton _)))) hp₃p₄).1 hc₅₁₂₃₄
    rw [Set.insert_comm] at hc₅₁₂ hc₅₃₄
    have hs₁₅₂ := oangle_eq_zero_or_eq_pi_iff_collinear.2 hc₅₁₂
    have hs₃₅₄ := oangle_eq_zero_or_eq_pi_iff_collinear.2 hc₅₃₄
    rw [← Real.Angle.sign_eq_zero_iff] at hs₁₅₂ hs₃₅₄
    rw [hs₁₅₂, hs₃₅₄]

Goal state after:
case neg
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p₁ p₂ p₃ p₄ p₅ : P
hp₁p₂ : p₁ ≠ p₂
hp₃p₄ : p₃ ≠ p₄
hc : Collinear ℝ {p₁, p₂, p₃, p₄}
hr : SameRay ℝ (p₂ -ᵥ p₁) (p₄ -ᵥ p₃)
hc₅₁₂ : ¬Collinear ℝ {p₅, p₁, p₂}
⊢ (∡ p₁ p₅ p₂).sign = (∡ p₃ p₅ p₄).sign
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.RightAngle

Goal state before:
pp: V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
hd2 : Fact (finrank ℝ V = 2)
o : Orientation ℝ V (Fin 2)
x : V
h : x ≠ 0
r : ℝ
⊢ o.oangle (x - r • (o.rotation ↑(π / 2)) x) x = ↑(Real.arctan r)

Tactic:
by
  by_cases hr : r = 0; · simp [hr]
  have hx : x = r⁻¹ • o.rotation (π / 2 : ℝ) (-(r • o.rotation (π / 2 : ℝ) x)) := by
    simp [hr, ← Real.Angle.coe_add]
  rw [sub_eq_add_neg, add_comm]
  nth_rw 3 [hx]
  nth_rw 2 [hx]
  rw [o.oangle_add_left_smul_rotation_pi_div_two, inv_inv]
  simpa [hr] using h

Goal state after:
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.RightAngle

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p₁ p₂ p₃ : P
h : ∡ p₁ p₂ p₃ = ↑(π / 2)
⊢ (∡ p₂ p₃ p₁).sin * dist p₁ p₃ = dist p₁ p₂

Tactic:
have hs : (∡ p₂ p₃ p₁).sign = 1 := by rw [oangle_rotate_sign, h, Real.Angle.sign_coe_pi_div_two]
  rw [oangle_eq_angle_of_sign_eq_one hs, Real.Angle.sin_coe,
    sin_angle_mul_dist_of_angle_eq_pi_div_two (angle_eq_pi_div_two_of_oangle_eq_pi_div_two h)]

Goal state after:
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Basic

Goal state before:
pp: case neg
V : Type u_1
inst✝² : NormedAddCommGroup V
inst✝¹ : InnerProductSpace ℝ V
inst✝ : Fact (finrank ℝ V = 2)
o : Orientation ℝ V (Fin 2)
x y z : V
hx : x ≠ 0
hz : z ≠ 0
hy : ¬y = 0
hr : ¬SameRay ℝ x z
hs : ¬(o.oangle x y).sign = (o.oangle y z).sign
hn : o.oangle x y ≠ o.oangle y z
⊢ InnerProductGeometry.angle x y = InnerProductGeometry.angle y z ↔ o.oangle x y = o.oangle y z

Tactic:
simp only [hn, iff_false]

Goal state after:
case neg
V : Type u_1
inst✝² : NormedAddCommGroup V
inst✝¹ : InnerProductSpace ℝ V
inst✝ : Fact (finrank ℝ V = 2)
o : Orientation ℝ V (Fin 2)
x y z : V
hx : x ≠ 0
hz : z ≠ 0
hy : ¬y = 0
hr : ¬SameRay ℝ x z
hs : ¬(o.oangle x y).sign = (o.oangle y z).sign
hn : o.oangle x y ≠ o.oangle y z
⊢ ¬InnerProductGeometry.angle x y = InnerProductGeometry.angle y z
Module: Mathlib.Geometry.Euclidean.SignedDist

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
v w : V
p q : P
⊢ -⟪NormedSpace.normalize v, w⟫ + ((signedDist v) p) q = ⟪NormedSpace.normalize v, -w⟫ + ((signedDist v) p) q

Tactic:
inner_neg_right

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
v w : V
p q : P
⊢ -⟪NormedSpace.normalize v, w⟫ + ((signedDist v) p) q = -⟪NormedSpace.normalize v, w⟫ + ((signedDist v) p) q
Module: Mathlib.Geometry.Euclidean.SignedDist

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
v : V
p q : P
h : ⟪v, q -ᵥ p⟫ = 0
⊢ ((signedDist v) p) q = 0

Tactic:
by
  simpa using signedDist_right_congr p h

Goal state after:
Module: Mathlib.Geometry.Euclidean.Angle.Bisector

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p p' : P
s₁ s₂ : AffineSubspace ℝ P
hp'₁ : p' ∈ s₁
hp'₂ : p' ∈ s₂
hne : ↑((orthogonalProjection s₁) p) ≠ ↑((orthogonalProjection s₂) p)
h : dist p ↑((orthogonalProjection s₁) p) = dist p ↑((orthogonalProjection s₂) p)
this✝¹ : Nonempty ↥s₁
this✝ : Nonempty ↥s₂
this : Nonempty ↥(s₁ ⊓ s₂)
hp₁ : ↑((orthogonalProjection s₁) p) ≠ p'
hp₂ : ↑((orthogonalProjection s₂) p) ≠ p'
hc : Collinear ℝ {p', ↑((orthogonalProjection s₁) p), ↑((orthogonalProjection s₂) p)}
h₁ : ↑((orthogonalProjection s₁) p) ∈ line[ℝ, p', ↑((orthogonalProjection s₂) p)]
h₁' : ↑((orthogonalProjection s₁) p) ∈ s₁ ⊓ s₂
⊢ ↑((orthogonalProjection s₁) p) = ↑((orthogonalProjection (s₁ ⊓ s₂)) p)

Tactic:
← orthogonalProjection_orthogonalProjection_of_le inf_le_left,

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁵ : NormedAddCommGroup V
inst✝⁴ : InnerProductSpace ℝ V
inst✝³ : MetricSpace P
inst✝² : NormedAddTorsor V P
inst✝¹ : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p p' : P
s₁ s₂ : AffineSubspace ℝ P
hp'₁ : p' ∈ s₁
hp'₂ : p' ∈ s₂
hne : ↑((orthogonalProjection s₁) p) ≠ ↑((orthogonalProjection s₂) p)
h : dist p ↑((orthogonalProjection s₁) p) = dist p ↑((orthogonalProjection s₂) p)
this✝¹ : Nonempty ↥s₁
this✝ : Nonempty ↥s₂
this : Nonempty ↥(s₁ ⊓ s₂)
hp₁ : ↑((orthogonalProjection s₁) p) ≠ p'
hp₂ : ↑((orthogonalProjection s₂) p) ≠ p'
hc : Collinear ℝ {p', ↑((orthogonalProjection s₁) p), ↑((orthogonalProjection s₂) p)}
h₁ : ↑((orthogonalProjection s₁) p) ∈ line[ℝ, p', ↑((orthogonalProjection s₂) p)]
h₁' : ↑((orthogonalProjection s₁) p) ∈ s₁ ⊓ s₂
⊢ ↑((orthogonalProjection s₁) p) = ↑((orthogonalProjection (s₁ ⊓ s₂)) ↑((orthogonalProjection s₁) p))
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Affine

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
p₁ p₂ p₃ p₄ : P
h₁₂ : p₁ ≠ p₂
ha : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ p₄ + ↑π
hs : line[ℝ, p₁, p₂].SSameSide p₃ p₄
⊢ ∠ p₁ p₂ p₃ = (∠ p₁ p₂ p₄ + π) / 2

Tactic:
by
  have h₃₂ : p₃ ≠ p₂ := by
    rintro rfl
    exact hs.left_notMem (right_mem_affineSpan_pair _ _ _)
  have h₄₂ : p₄ ≠ p₂ := by
    rintro rfl
    exact hs.right_notMem (right_mem_affineSpan_pair _ _ _)
  have ha' : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ (AffineEquiv.pointReflection ℝ p₂ p₄) := by
    rw [oangle_pointReflection_right h₃₂ h₄₂]
    exact ha
  have hs' : line[ℝ, p₁, p₂].SOppSide p₄ (AffineEquiv.pointReflection ℝ p₂ p₄) :=
    AffineSubspace.sOppSide_pointReflection (right_mem_affineSpan_pair _ _ _) (hs.right_notMem)
  obtain h := angle_eq_pi_sub_angle_div_two_of_oangle_eq_of_sOppSide h₁₂ ha' (hs.trans_sOppSide hs')
  rw [angle_pointReflection_right] at h
  linear_combination h

Goal state after:
Module: Mathlib.Geometry.Euclidean.Sphere.Basic

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Set P
p : Fin 3 → P
hps : Set.range p ⊆ s
hpi : Function.Injective p
v : V
hv0 : v ≠ 0
c : P
r : ℝ
hs : ∀ p ∈ s, dist p c = r
hs' : ∀ (i : Fin 3), dist (p i) c = r
f : Fin 3 → ℝ
hf : ∀ (i : Fin 3), p i = f i • v +ᵥ p 0
i : Fin 3
⊢ dist (f i • v +ᵥ p 0) c = r

Tactic:
rw [← hf]

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Set P
p : Fin 3 → P
hps : Set.range p ⊆ s
hpi : Function.Injective p
v : V
hv0 : v ≠ 0
c : P
r : ℝ
hs : ∀ p ∈ s, dist p c = r
hs' : ∀ (i : Fin 3), dist (p i) c = r
f : Fin 3 → ℝ
hf : ∀ (i : Fin 3), p i = f i • v +ᵥ p 0
i : Fin 3
⊢ dist (p i) c = r
Module: Mathlib.Geometry.Euclidean.Sphere.OrthRadius

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
p : P
⊢ p ∈ mk' p (ℝ ∙ (p -ᵥ s.center))ᗮ ∧ s.center -ᵥ p ∈ (mk' p (ℝ ∙ (p -ᵥ s.center))ᗮ).directionᗮ

Tactic:
rw [← Submodule.neg_mem_iff]

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
p : P
⊢ p ∈ mk' p (ℝ ∙ (p -ᵥ s.center))ᗮ ∧ -(s.center -ᵥ p) ∈ (mk' p (ℝ ∙ (p -ᵥ s.center))ᗮ).directionᗮ
Module: Mathlib.Geometry.Euclidean.Sphere.Tangent

Goal state before:
pp: case e'_4
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
as : AffineSubspace ℝ P
p : P
h : s.IsTangentAt p as
⊢ s.radius = dist s.center p

Tactic:
mem_sphere'.1 h.mem_sphere

Goal state after:
case e'_4
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
as : AffineSubspace ℝ P
p : P
h : s.IsTangentAt p as
⊢ s.radius = s.radius
Module: Mathlib.Geometry.Euclidean.Sphere.Basic

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
p₁ p₂ : P
s : Sphere P
hp₁ : p₁ ∈ s
hp₂ : p₂ ∈ s
hp₁p₂ : p₁ ≠ p₂
hp₁' : ‖p₁ -ᵥ s.center‖ = s.radius
hp₂' : ‖p₂ -ᵥ s.center‖ = s.radius
hd : s.radius ^ 2 = ‖p₂ -ᵥ p₁‖ ^ 2 + 2 * ⟪p₂ -ᵥ p₁, -(s.center -ᵥ p₁)⟫ + s.radius ^ 2
⊢ 0 < ⟪p₂ -ᵥ p₁, s.center -ᵥ p₁⟫

Tactic:
inner_neg_right

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
p₁ p₂ : P
s : Sphere P
hp₁ : p₁ ∈ s
hp₂ : p₂ ∈ s
hp₁p₂ : p₁ ≠ p₂
hp₁' : ‖p₁ -ᵥ s.center‖ = s.radius
hp₂' : ‖p₂ -ᵥ s.center‖ = s.radius
hd : s.radius ^ 2 = ‖p₂ -ᵥ p₁‖ ^ 2 + 2 * -⟪p₂ -ᵥ p₁, s.center -ᵥ p₁⟫ + s.radius ^ 2
⊢ 0 < ⟪p₂ -ᵥ p₁, s.center -ᵥ p₁⟫
Module: Mathlib.Geometry.Euclidean.Sphere.Basic

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
p₁ p₂ : P
⊢ s.IsDiameter p₁ p₂ ↔ p₁ ∈ s ∧ p₂ ∈ s ∧ Wbtw ℝ p₁ s.center p₂

Tactic:
refine ⟨fun h ↦ ⟨h.left_mem, h.right_mem, h.wbtw⟩, fun ⟨h₁, h₂, hr⟩ ↦ ?_⟩
  have hd := hr.dist_add_dist
  rw [mem_sphere.1 h₁, mem_sphere'.1 h₂, ← two_mul, eq_comm] at hd
  exact isDiameter_iff_mem_and_mem_and_dist.2 ⟨h₁, h₂, hd⟩

Goal state after:
Module: Mathlib.Geometry.Euclidean.Sphere.OrthRadius

Goal state before:
pp: case inl.inl.inl
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
s : Sphere P
h : dist s.center s.center < s.radius
hs : Subsingleton V
hs' : Subsingleton P
⊢ Metric.sphere s.center s.radius ∩ ↑(s.orthRadius s.center) = ∅ ↔
    Module.finrank ℝ V = 1 ∧ ¬s.center = s.center ∨ Subsingleton V

Tactic:
simp [hs, Metric.sphere_eq_empty_of_subsingleton (dist_nonneg.trans_lt h).ne']

Goal state after:
Module: Mathlib.Geometry.Euclidean.Angle.Incenter

Goal state before:
pp: case inl.inl
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
t : Triangle ℝ P
i₁ i₂ i₃ : Fin 3
h₁₂ : i₁ ≠ i₂
h₁₃ : i₁ ≠ i₃
h₂₃ : i₂ ≠ i₃
signs : Finset (Fin 3)
h₁ : ∡ (t.points i₂) (t.points i₁) (excenter t signs) = ∡ (excenter t signs) (t.points i₁) (t.points i₃)
h₂ : ∡ (t.points i₃) (t.points i₂) (excenter t signs) = ∡ (excenter t signs) (t.points i₂) (t.points i₁) + ↑π
h₁' : excenter t signs = incenter t
h₂' : excenter t signs = excenter t {i₃}
⊢ excenter t signs = excenter t {i₁}

Tactic:
rw [h₁'] at h₂'
      exfalso
      exact (t.excenter_singleton_ne_incenter _).symm h₂'

Goal state after:
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hi : i ≠ 0
⊢ ∑ j, ⟪s.points i -ᵥ s.points 0, (s.height j)⁻¹ ^ 2 • (s.points j -ᵥ s.altitudeFoot j)⟫ = 0

Tactic:
← Finset.add_sum_erase _ _ (Finset.mem_univ 0),

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hi : i ≠ 0
⊢ ⟪s.points i -ᵥ s.points 0, (s.height 0)⁻¹ ^ 2 • (s.points 0 -ᵥ s.altitudeFoot 0)⟫ +
      ∑ x ∈ Finset.univ.erase 0, ⟪s.points i -ᵥ s.points 0, (s.height x)⁻¹ ^ 2 • (s.points x -ᵥ s.altitudeFoot x)⟫ =
    0
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: case e'_2.e'_6.refine_2
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hi : i ≠ 0
j : Fin (n + 1)
hj : j ≠ i ∧ j ≠ 0
⊢ ∃ x ∈ {j}ᶜ, s.points x = s.points 0

Tactic:
· exact ⟨0, hj.2.symm, rfl⟩

Goal state after:
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: case e'_3
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hi : i ≠ 0
⊢ 0 =
    ⟪s.points i -ᵥ s.points 0, (s.height 0)⁻¹ ^ 2 • (s.points 0 -ᵥ s.altitudeFoot 0)⟫ +
      ⟪s.points i -ᵥ s.points 0, (s.height i)⁻¹ ^ 2 • (s.points i -ᵥ s.altitudeFoot i)⟫

Tactic:
rw [inner_smul_right, inner_smul_right, inner_vsub_vsub_altitudeFoot_eq_height_sq _ hi,
      ← neg_vsub_eq_vsub_rev, inner_neg_left, inner_vsub_vsub_altitudeFoot_eq_height_sq _ hi.symm,
      mul_neg, inv_pow]

Goal state after:
case e'_3
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hi : i ≠ 0
⊢ 0 = -((s.height 0 ^ 2)⁻¹ * s.height 0 ^ 2) + (s.height i)⁻¹ ^ 2 * s.height i ^ 2
Module: Mathlib.Geometry.Euclidean.Angle.Sphere

Goal state before:
pp: V : Type u_3
P : Type u_4
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
s : Sphere P
p₁ p₂ : P
hp₁ : p₁ ∈ s
hp₂ : p₂ ∈ s
h : p₁ ≠ p₂
r : ℝ
hr : r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂ = s.center
⊢ ((∡ p₂ p₁ (r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂)).tan / 2) •
        («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ
      midpoint ℝ p₁ p₂ =
    r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂

Tactic:
← oangle_midpoint_rev_left,

Goal state after:
V : Type u_3
P : Type u_4
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
hd2 : Fact (finrank ℝ V = 2)
inst✝ : Oriented ℝ V (Fin 2)
s : Sphere P
p₁ p₂ : P
hp₁ : p₁ ∈ s
hp₂ : p₂ ∈ s
h : p₁ ≠ p₂
r : ℝ
hr : r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂ = s.center
⊢ ((∡ (midpoint ℝ p₁ p₂) p₁ (r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂)).tan / 2) •
        («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ
      midpoint ℝ p₁ p₂ =
    r • («o».rotation ↑(π / 2)) (p₂ -ᵥ p₁) +ᵥ midpoint ℝ p₁ p₂
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
h : ∑ i, s.excenterWeights ∅ i = 1
i : Fin (n + 1)
hp : 1 ≤ s.excenterWeights ∅ i
j : Fin (n + 1)
hj : j ≠ i
⊢ False

Tactic:
rw [← Finset.sum_add_sum_compl {j, i}, Finset.sum_pair hj] at h

Goal state after:
V : Type u_1
P : Type u_2
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace ℝ V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
n : ℕ
inst✝ : NeZero n
s : Simplex ℝ P n
i : Fin (n + 1)
hp : 1 ≤ s.excenterWeights ∅ i
j : Fin (n + 1)
h : s.excenterWeights ∅ j + s.excenterWeights ∅ i + ∑ i ∈ {j, i}ᶜ, s.excenterWeights ∅ i = 1
hj : j ≠ i
⊢ False
Module: Mathlib.Geometry.Euclidean.Triangle

Goal state before:
pp: case inr
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
hx : x ≠ 0
hy : y ≠ 0
hxy : x ≠ -y
this : x + y ≠ 0
⊢ ⟪x, y⟫ * ‖x + y‖ ^ 2 = ⟪x, x + y⟫ * ⟪y, x + y⟫ - √(⟪x, x⟫ * ⟪y, y⟫ - ⟪x, y⟫ * ⟪x, y⟫) ^ 2

Tactic:
rw [Real.sq_sqrt (sub_nonneg_of_le (real_inner_mul_inner_self_le x y))]

Goal state after:
case inr
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
hx : x ≠ 0
hy : y ≠ 0
hxy : x ≠ -y
this : x + y ≠ 0
⊢ ⟪x, y⟫ * ‖x + y‖ ^ 2 = ⟪x, x + y⟫ * ⟪y, x + y⟫ - (⟪x, x⟫ * ⟪y, y⟫ - ⟪x, y⟫ * ⟪x, y⟫)
Module: Mathlib.Geometry.Euclidean.Circumcenter

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
n : ℕ
s : Simplex ℝ P (n + 1)
⊢ 0 < s.circumradius

Tactic:
refine lt_of_le_of_ne s.circumradius_nonneg ?_

Goal state after:
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
n : ℕ
s : Simplex ℝ P (n + 1)
⊢ 0 ≠ s.circumradius
Module: Mathlib.Geometry.Euclidean.Triangle

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
p₁ p₂ p₃ : P
⊢ dist p₁ p₃ * dist p₁ p₃ =
    dist p₁ p₂ * dist p₁ p₂ + dist p₃ p₂ * dist p₃ p₂ - 2 * dist p₁ p₂ * dist p₃ p₂ * Real.cos (∠ p₁ p₂ p₃)

Tactic:
by
  rw [dist_eq_norm_vsub V p₁ p₃, dist_eq_norm_vsub V p₁ p₂, dist_eq_norm_vsub V p₃ p₂]
  unfold angle
  convert!
    norm_sub_sq_eq_norm_sq_add_norm_sq_sub_two_mul_norm_mul_norm_mul_cos_angle (p₁ -ᵥ p₂ : V)
      (p₃ -ᵥ p₂ : V)
  · exact (vsub_sub_vsub_cancel_right p₁ p₃ p₂).symm
  · exact (vsub_sub_vsub_cancel_right p₁ p₃ p₂).symm

Goal state after:
Module: Mathlib.Geometry.Euclidean.Triangle

Goal state before:
pp: case pos
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
a b c p : P
hb : a ≠ b
hc : a ≠ c
hp : Wbtw ℝ b p c
pb : p = b
⊢ ∠ b a p + ∠ p a c = ∠ b a c

pp: case neg
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
a b c p : P
hb : a ≠ b
hc : a ≠ c
hp : Wbtw ℝ b p c
pb : ¬p = b
⊢ ∠ b a p + ∠ p a c = ∠ b a c

Tactic:
· simpa [pb] using angle_self_of_ne hb.symm

Goal state after:
case neg
V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
a b c p : P
hb : a ≠ b
hc : a ≠ c
hp : Wbtw ℝ b p c
pb : ¬p = b
⊢ ∠ b a p + ∠ p a c = ∠ b a c
Module: Mathlib.Geometry.Euclidean.Inversion.ImageHyperplane

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
c y : P
R : ℝ
hR : R ≠ 0
hy : y ≠ c
⊢ inversion c R '' sphere y (dist y c) = insert c ↑(perpBisector c (inversion c R y))

Tactic:
by
  rw [image_eq_preimage_of_inverse (inversion_involutive _ hR) (inversion_involutive _ hR),
    preimage_inversion_sphere_dist_center hR hy]

Goal state after:
Module: Mathlib.Geometry.Euclidean.MongePoint

Goal state before:
pp: V : Type u_1
P : Type u_2
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
n : ℕ
s : Simplex ℝ P n
S : AffineSubspace ℝ P
hS : affineSpan ℝ (Set.range s.points) ≤ S
⊢ ↑(s.restrict S hS).mongePoint = s.mongePoint

Tactic:
by
  have := Nonempty.map (AffineSubspace.inclusion hS) inferInstance
  simp_rw [mongePoint]
  rw [← Simplex.centroid, ← Simplex.centroid]
  simp [centroid_restrict, circumcenter_restrict]

Goal state after:
Module: Mathlib.Geometry.Euclidean.Sphere.Ptolemy

Goal state before:
pp: V : Type u_1
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
P : Type u_2
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
a b c d p : P
h : Cospherical {a, b, c, d}
hapc : ∠ a p c = π
hbpd : ∠ b p d = π
h' : Cospherical {a, c, b, d}
hmul : dist a p * dist c p = dist b p * dist d p
hbp : dist b p ≠ 0
h₁ : dist c d = dist c p / dist b p * dist a b
⊢ dist a b * dist c d + dist b c * dist d a = dist a c * dist b d

Tactic:
have h₂ : dist d a = dist a p / dist b p * dist b c := by
    rw [dist_mul_of_eq_angle_of_dist_mul c p b d p a, dist_comm c b]
    · rwa [angle_comm, angle_eq_angle_of_angle_eq_pi_of_angle_eq_pi]; rwa [angle_comm]
    all_goals simp [field, mul_comm, hmul]

Goal state after:
V : Type u_1
inst✝³ : NormedAddCommGroup V
inst✝² : InnerProductSpace ℝ V
P : Type u_2
inst✝¹ : MetricSpace P
inst✝ : NormedAddTorsor V P
a b c d p : P
h : Cospherical {a, b, c, d}
hapc : ∠ a p c = π
hbpd : ∠ b p d = π
h' : Cospherical {a, c, b, d}
hmul : dist a p * dist c p = dist b p * dist d p
hbp : dist b p ≠ 0
h₁ : dist c d = dist c p / dist b p * dist a b
h₂ : dist d a = dist a p / dist b p * dist b c
⊢ dist a b * dist c d + dist b c * dist d a = dist a c * dist b d