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

Goal state before:
pp: case mp
𝕜 : Type u_1
V : Type u_2
P : Type u_3
inst✝⁵ : RCLike 𝕜
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace 𝕜 V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
s : AffineSubspace 𝕜 P
inst✝ : s.direction.HasOrthogonalProjection
p₁ p₂ : P
hp₂ : p₂ ∈ s
this : Nonempty ↥s
h : dist p₁ ↑((orthogonalProjection s) p₁) * dist p₁ ↑((orthogonalProjection s) p₁) = dist p₂ p₁ * dist p₂ p₁
⊢ ↑((orthogonalProjection s) p₁) = p₂

Tactic:
dist_sq_eq_dist_orthogonalProjection_sq_add_dist_orthogonalProjection_sq _ hp₂,

Goal state after:
case mp
𝕜 : Type u_1
V : Type u_2
P : Type u_3
inst✝⁵ : RCLike 𝕜
inst✝⁴ : NormedAddCommGroup V
inst✝³ : InnerProductSpace 𝕜 V
inst✝² : MetricSpace P
inst✝¹ : NormedAddTorsor V P
s : AffineSubspace 𝕜 P
inst✝ : s.direction.HasOrthogonalProjection
p₁ p₂ : P
hp₂ : p₂ ∈ s
this : Nonempty ↥s
h :
  dist p₁ ↑((orthogonalProjection s) p₁) * dist p₁ ↑((orthogonalProjection s) p₁) =
    dist p₂ ↑((orthogonalProjection s) p₁) * dist p₂ ↑((orthogonalProjection s) p₁) +
      dist p₁ ↑((orthogonalProjection s) p₁) * dist p₁ ↑((orthogonalProjection s) p₁)
⊢ ↑((orthogonalProjection s) p₁) = p₂
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Rotation

Goal state before:
pp: case hy
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 : V
hx : x ≠ 0
hy : y ≠ 0
θ : Real.Angle
⊢ (o.kahler x) y ≠ 0

Tactic:
· exact o.kahler_ne_zero hx hy

Goal state after:
Module: Mathlib.Geometry.Euclidean.Angle.Unoriented.Affine

Goal state before:
pp: case right
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
hp₁p₂ : p₂ -ᵥ p₁ ≠ 0
r : ℝ
hr : r < 0
hpr : p₃ -ᵥ p₂ = r • (p₁ -ᵥ p₂)
⊢ p₃ -ᵥ p₁ = -r • -(p₁ -ᵥ p₂) + 1 • -(p₁ -ᵥ p₂)

Tactic:
smul_neg

Goal state after:
case right
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
hp₁p₂ : p₂ -ᵥ p₁ ≠ 0
r : ℝ
hr : r < 0
hpr : p₃ -ᵥ p₂ = r • (p₁ -ᵥ p₂)
⊢ p₃ -ᵥ p₁ = -(-r • (p₁ -ᵥ p₂)) + 1 • -(p₁ -ᵥ p₂)
Module: Mathlib.Geometry.Euclidean.Altitude

Goal state before:
pp: case a.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
s : Simplex ℝ P n
inst✝ : n.AtLeastTwo
i j : Fin (n + 1)
hij : i ≠ j
r : ℝ
hr : r ≠ 0
h : s.points j -ᵥ s.altitudeFoot j = r • (s.points i -ᵥ s.altitudeFoot i)
hk : ∃ k, k ≠ i ∧ k ≠ j
hs :
  vectorSpan ℝ (Set.range s.points) =
    vectorSpan ℝ (Set.range (s.faceOpposite i).points) ⊔ vectorSpan ℝ (Set.range (s.faceOpposite j).points)
⊢ s.points j -ᵥ s.altitudeFoot j ∈ (vectorSpan ℝ (Set.range (s.faceOpposite i).points))ᗮ ∧
    s.points j -ᵥ s.altitudeFoot j ∈ (vectorSpan ℝ (Set.range (s.faceOpposite j).points))ᗮ

Tactic:
refine ⟨?_, ?_⟩

Goal state after:
case a.refine_2.refine_1
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
s : Simplex ℝ P n
inst✝ : n.AtLeastTwo
i j : Fin (n + 1)
hij : i ≠ j
r : ℝ
hr : r ≠ 0
h : s.points j -ᵥ s.altitudeFoot j = r • (s.points i -ᵥ s.altitudeFoot i)
hk : ∃ k, k ≠ i ∧ k ≠ j
hs :
  vectorSpan ℝ (Set.range s.points) =
    vectorSpan ℝ (Set.range (s.faceOpposite i).points) ⊔ vectorSpan ℝ (Set.range (s.faceOpposite j).points)
⊢ s.points j -ᵥ s.altitudeFoot j ∈ (vectorSpan ℝ (Set.range (s.faceOpposite i).points))ᗮ

case a.refine_2.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
s : Simplex ℝ P n
inst✝ : n.AtLeastTwo
i j : Fin (n + 1)
hij : i ≠ j
r : ℝ
hr : r ≠ 0
h : s.points j -ᵥ s.altitudeFoot j = r • (s.points i -ᵥ s.altitudeFoot i)
hk : ∃ k, k ≠ i ∧ k ≠ j
hs :
  vectorSpan ℝ (Set.range s.points) =
    vectorSpan ℝ (Set.range (s.faceOpposite i).points) ⊔ vectorSpan ℝ (Set.range (s.faceOpposite j).points)
⊢ s.points j -ᵥ s.altitudeFoot j ∈ (vectorSpan ℝ (Set.range (s.faceOpposite j).points))ᗮ
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 : V
hx : ¬x = 0
r : ℝ
h : SameRay ℝ x (r • x)
⊢ x = 0 ∨ ∃ r_1, r • x = r_1 • x

Tactic:
exact Or.inr ⟨r, rfl⟩

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

Goal state before:
pp: case hx
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
hy : y ≠ 0
hz : z ≠ 0
⊢ (o.kahler x) y ≠ 0

pp: case hy
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
hy : y ≠ 0
hz : z ≠ 0
⊢ (o.kahler y) z ≠ 0

Tactic:
· exact o.kahler_ne_zero hx hy

Goal state after:
case hy
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
hy : y ≠ 0
hz : z ≠ 0
⊢ (o.kahler y) z ≠ 0
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 : V
hx : ¬x = 0
hy : ¬y = 0
⊢ (o.kahler x) y ≠ 0

Tactic:
· exact o.kahler_ne_zero hx hy

Goal state after:
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 p₅ p₆ : P
h₁₂₄₅ : ℝ ∙ (p₁ -ᵥ p₂) = ℝ ∙ (p₄ -ᵥ p₅)
h₃₂₆₅ : ℝ ∙ (p₃ -ᵥ p₂) = ℝ ∙ (p₆ -ᵥ p₅)
⊢ 2 • ∡ p₁ p₂ p₃ = 2 • ∡ p₄ p₅ p₆

Tactic:
exact o.two_zsmul_oangle_of_span_eq_of_span_eq h₁₂₄₅ h₃₂₆₅

Goal state after:
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 y : V
h : o.oangle x y = ↑(π / 2)
hs : (o.oangle x (x + y)).sign = 1
⊢ ↑(InnerProductGeometry.angle x (x + y)) = ↑(Real.arcsin (‖y‖ / ‖x + y‖))

Tactic:
InnerProductGeometry.angle_add_eq_arcsin_of_inner_eq_zero
      (o.inner_eq_zero_of_oangle_eq_pi_div_two h)
      (Or.inl (o.left_ne_zero_of_oangle_eq_pi_div_two h))

Goal state after:
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 y : V
h : o.oangle x y = ↑(π / 2)
hs : (o.oangle x (x + y)).sign = 1
⊢ ↑(Real.arcsin (‖y‖ / ‖x + y‖)) = ↑(Real.arcsin (‖y‖ / ‖x + y‖))
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Affine

Goal state before:
pp: case neg.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)
p₁ p₁' p₂ p₃ : P
h : Collinear ℝ {p₁, p₂, p₁'}
hp₁p₂ : p₁ ≠ p₂
hp₁'p₂ : p₁' ≠ p₂
hp₃p₂ : ¬p₃ = p₂
hw : Wbtw ℝ p₁ p₂ p₁'
hw' : Sbtw ℝ p₁ p₂ p₁'
⊢ 2 • ∡ p₁' p₂ p₃ + 2 • ↑π = 2 • ∡ p₁' p₂ p₃

Tactic:
Real.Angle.two_zsmul_coe_pi,

Goal state after:
case neg.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)
p₁ p₁' p₂ p₃ : P
h : Collinear ℝ {p₁, p₂, p₁'}
hp₁p₂ : p₁ ≠ p₂
hp₁'p₂ : p₁' ≠ p₂
hp₃p₂ : ¬p₃ = p₂
hw : Wbtw ℝ p₁ p₂ p₁'
hw' : Sbtw ℝ p₁ p₂ p₁'
⊢ 2 • ∡ p₁' p₂ p₃ + 0 = 2 • ∡ p₁' p₂ p₃
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)
this : Nonempty ↥s
⊢ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(π / 2) ∨ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(-π / 2)

Tactic:
have hpne : p ≠ orthogonalProjection s p := Ne.symm (orthogonalProjection_eq_self_iff.not.2 hp)

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
hpne : p ≠ ↑((orthogonalProjection s) p)
⊢ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(π / 2) ∨ ∡ p (↑((orthogonalProjection s) p)) p' = ↑(-π / 2)
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 : V
r : ℝ
h : ¬(o.oangle x y = 0 ∨ o.oangle x y = ↑π)
h' : ∀ (r' : ℝ), o.oangle x (r' • x + y) ≠ 0 ∧ o.oangle x (r' • x + y) ≠ ↑π
s : Set (V × V) := (fun r' ↦ (x, r' • x + y)) '' Set.univ
hc : IsConnected s
hf : ContinuousOn (fun z ↦ o.oangle z.1 z.2) s
hs : ∀ z ∈ s, o.oangle z.1 z.2 ≠ 0 ∧ o.oangle z.1 z.2 ≠ ↑π
hx : (x, y) ∈ s
⊢ (o.oangle x (r • x + y)).sign = (o.oangle x y).sign

Tactic:
have hy : (x, r • x + y) ∈ s := Set.mem_image_of_mem _ (Set.mem_univ _)

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 : V
r : ℝ
h : ¬(o.oangle x y = 0 ∨ o.oangle x y = ↑π)
h' : ∀ (r' : ℝ), o.oangle x (r' • x + y) ≠ 0 ∧ o.oangle x (r' • x + y) ≠ ↑π
s : Set (V × V) := (fun r' ↦ (x, r' • x + y)) '' Set.univ
hc : IsConnected s
hf : ContinuousOn (fun z ↦ o.oangle z.1 z.2) s
hs : ∀ z ∈ s, o.oangle z.1 z.2 ≠ 0 ∧ o.oangle z.1 z.2 ≠ ↑π
hx : (x, y) ∈ s
hy : (x, r • x + y) ∈ s
⊢ (o.oangle x (r • x + y)).sign = (o.oangle x y).sign
Module: Mathlib.Geometry.Euclidean.Angle.Oriented.Basic

Goal state before:
pp: 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 : V
⊢ (o.oangle (x - y) y).sign = (o.oangle x y).sign

Tactic:
rw [← o.oangle_sign_sub_smul_left x y 1, one_smul]

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 : V
r₁ r₂ r₃ r₄ : ℝ
hr₁ : ¬r₁ = 0
⊢ SignType.sign (r₁ * r₄ - r₃ * r₂) * (o.oangle x y).sign = SignType.sign (r₁ * r₄ - r₂ * r₃) * (o.oangle x y).sign

Tactic:
mul_comm r₃

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 : V
r₁ r₂ r₃ r₄ : ℝ
hr₁ : ¬r₁ = 0
⊢ SignType.sign (r₁ * r₄ - r₂ * r₃) * (o.oangle x y).sign = SignType.sign (r₁ * r₄ - r₂ * r₃) * (o.oangle x y).sign
Module: Mathlib.Geometry.Euclidean.Angle.Bisector

Goal state before:
pp: case pos
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
p p' : P
s₁ s₂ : AffineSubspace ℝ P
inst✝¹ : s₁.direction.HasOrthogonalProjection
inst✝ : s₂.direction.HasOrthogonalProjection
hp'₁ : p' ∈ s₁
hp'₂ : p' ∈ s₂
this✝ : Nonempty ↥s₁
this : Nonempty ↥s₂
h' : p ∈ s₁ ∨ p ∈ s₂
⊢ dist p ↑((orthogonalProjection s₁) p) = dist p ↑((orthogonalProjection s₂) p) ↔
    ∠ p p' ↑((orthogonalProjection s₁) p) = ∠ p p' ↑((orthogonalProjection s₂) p)

pp: case neg
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
p p' : P
s₁ s₂ : AffineSubspace ℝ P
inst✝¹ : s₁.direction.HasOrthogonalProjection
inst✝ : s₂.direction.HasOrthogonalProjection
hp'₁ : p' ∈ s₁
hp'₂ : p' ∈ s₂
this✝ : Nonempty ↥s₁
this : Nonempty ↥s₂
h' : ¬(p ∈ s₁ ∨ p ∈ s₂)
⊢ dist p ↑((orthogonalProjection s₁) p) = dist p ↑((orthogonalProjection s₂) p) ↔
    ∠ p p' ↑((orthogonalProjection s₁) p) = ∠ p p' ↑((orthogonalProjection s₂) p)

Tactic:
· exact dist_orthogonalProjection_eq_iff_angle_eq_aux hp'₁ hp'₂ h'

Goal state after:
case neg
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
p p' : P
s₁ s₂ : AffineSubspace ℝ P
inst✝¹ : s₁.direction.HasOrthogonalProjection
inst✝ : s₂.direction.HasOrthogonalProjection
hp'₁ : p' ∈ s₁
hp'₂ : p' ∈ s₂
this✝ : Nonempty ↥s₁
this : Nonempty ↥s₂
h' : ¬(p ∈ s₁ ∨ p ∈ s₂)
⊢ dist p ↑((orthogonalProjection s₁) p) = dist p ↑((orthogonalProjection s₂) p) ↔
    ∠ p p' ↑((orthogonalProjection s₁) p) = ∠ p p' ↑((orthogonalProjection s₂) p)
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
⊢ InnerProductGeometry.angle x y = InnerProductGeometry.angle y z ↔ o.oangle x y = o.oangle y z

Tactic:
have hn : o.oangle x y ≠ o.oangle y z := by grind

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 ↔ o.oangle x y = o.oangle y z
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)
hs : (∡ p₃ p₁ p₂).sign = 1
⊢ dist p₁ p₂ / (∡ p₃ p₁ p₂).cos = dist p₁ p₃

Tactic:
rw [oangle_eq_angle_of_sign_eq_one hs, angle_comm, Real.Angle.cos_coe, dist_comm p₁ p₃,
    dist_div_cos_angle_of_angle_eq_pi_div_two (angle_rev_eq_pi_div_two_of_oangle_eq_pi_div_two h)
      (Or.inr (left_ne_of_oangle_eq_pi_div_two h))]

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

Goal state before:
pp: P : Type u_2
inst✝ : MetricSpace P
s₁ s₂ : Sphere P
p : P
hs₁ : dist p s₁.center = s₁.radius
hs₂ : dist p s₂.center = s₂.radius
h : s₁.center = s₂.center
⊢ s₁.radius = s₂.radius

Tactic:
rw [← hs₁, ← hs₂, h]

Goal state after:
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
⊢ (s.orthRadius p).direction.HasOrthogonalProjection

Tactic:
rw [direction_orthRadius]
  infer_instance

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

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
as : AffineSubspace ℝ P
⊢ s.IsTangentAt s.center as ↔ s.radius = 0 ∧ s.center ∈ as

Tactic:
refine ⟨?_, ?_⟩

Goal state after:
case refine_1
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
⊢ s.IsTangentAt s.center as → s.radius = 0 ∧ s.center ∈ as

case refine_2
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
⊢ s.radius = 0 ∧ s.center ∈ as → s.IsTangentAt s.center as
Module: Mathlib.Geometry.Euclidean.Sphere.OrthRadius

Goal state before:
pp: case mpr
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
hp : dist p s.center = s.radius
p' : P
⊢ p' = p → p' ∈ s ∧ p' ∈ s.orthRadius p

Tactic:
· rintro rfl
    simpa using hp

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

Goal state before:
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
s₁ s₂ : Sphere P
as : AffineSubspace ℝ P
h : ∀ p ∈ as, ¬Wbtw ℝ s₁.center p s₂.center
⊢ (∃ p ∈ as, Wbtw ℝ s₁.center p s₂.center) ∨ ∀ p ∈ as, ¬Sbtw ℝ s₁.center p s₂.center

Tactic:
refine .inr ?_
    rintro p hp
    exact mt Sbtw.wbtw (h p hp)

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

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
s₁ s₂ : Sphere P
⊢ s₁.IsExtTangentAt s₂ s₁.center ↔ s₁.radius = 0 ∧ s₁.center ∈ s₂

Tactic:
refine ⟨?_, ?_⟩

Goal state after:
case refine_1
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
s₁ s₂ : Sphere P
⊢ s₁.IsExtTangentAt s₂ s₁.center → s₁.radius = 0 ∧ s₁.center ∈ s₂

case refine_2
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
s₁ s₂ : Sphere P
⊢ s₁.radius = 0 ∧ s₁.center ∈ s₂ → s₁.IsExtTangentAt s₂ s₁.center
Module: Mathlib.Geometry.Euclidean.Sphere.Tangent

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
s₁ s₂ : Sphere P
⊢ s₁.IsIntTangentAt s₂ s₁.center ↔ s₁.radius = 0 ∧ s₁.center ∈ s₂

Tactic:
refine ⟨?_, ?_⟩

Goal state after:
case refine_1
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
s₁ s₂ : Sphere P
⊢ s₁.IsIntTangentAt s₂ s₁.center → s₁.radius = 0 ∧ s₁.center ∈ s₂

case refine_2
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
s₁ s₂ : Sphere P
⊢ s₁.radius = 0 ∧ s₁.center ∈ s₂ → s₁.IsIntTangentAt s₂ s₁.center
Module: Mathlib.Geometry.Euclidean.Sphere.Tangent

Goal state before:
pp: case neg.refine_2
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
s₁ s₂ : Sphere P
h : dist s₁.center s₂.center = s₁.radius + s₂.radius
h₁ : 0 ≤ s₁.radius
h₂ : 0 ≤ s₂.radius
h0 : ¬s₁.radius + s₂.radius = 0
⊢ (AffineMap.lineMap s₁.center s₂.center) (s₁.radius / (s₁.radius + s₂.radius)) ∈ s₂

Tactic:
simp only [mem_sphere, dist_lineMap_right, Real.norm_eq_abs, h]
        rw [one_sub_div h0, add_sub_cancel_left, abs_div, abs_of_nonneg h₂,
          abs_of_nonneg (add_nonneg h₁ h₂)]
        field

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

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
s₁ s₂ : Sphere P
⊢ s₁.IsExtTangent s₂ ↔ dist s₁.center s₂.center = s₁.radius + s₂.radius ∧ 0 ≤ s₁.radius ∧ 0 ≤ s₂.radius

Tactic:
by
  refine ⟨fun h ↦ ⟨h.dist_center, ?_⟩, ?_⟩
  · rcases h with ⟨p, h₁, h₂, h⟩
    exact ⟨radius_nonneg_of_mem h₁, radius_nonneg_of_mem h₂⟩
  · rintro ⟨h, h₁, h₂⟩
    refine ⟨AffineMap.lineMap s₁.center s₂.center (s₁.radius / (s₁.radius + s₂.radius)), ?_⟩
    by_cases h0 : s₁.radius + s₂.radius = 0
    · simp only [h0, div_zero, AffineMap.lineMap_apply_zero, isExtTangentAt_center_iff, mem_sphere]
      exact ⟨by linarith, by linarith⟩
    · refine ⟨?_, ?_, ?_⟩
      · simp only [mem_sphere, dist_lineMap_left, norm_div, Real.norm_eq_abs, h, abs_of_nonneg h₁,
          abs_of_nonneg (add_nonneg h₁ h₂)]
        field
      · simp only [mem_sphere, dist_lineMap_right, Real.norm_eq_abs, h]
        rw [one_sub_div h0, add_sub_cancel_left, abs_div, abs_of_nonneg h₂,
          abs_of_nonneg (add_nonneg h₁ h₂)]
        field
      · simp only [wbtw_lineMap_iff]
        refine .inr ⟨?_, ?_⟩
        · positivity
        · rw [div_le_one (by positivity)]
          linarith

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

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
inst✝ : Nontrivial V
s₁ s₂ : Sphere P
h : s₂.center = s₁.center
h₁ : 0 ≤ s₁.radius
h₂ : 0 ≤ s₂.radius
h0 : ¬s₁.center = s₂.center
ha : |s₂.radius - s₁.radius| = s₂.radius - s₁.radius
hr0 : s₂.radius - s₁.radius = 0
⊢ False

Tactic:
exact h0 h.symm

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

Goal state before:
pp: V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
⊢ Real.sin (angle x y) * ‖x‖ = Real.sin (angle y (x - y)) * ‖x - y‖

Tactic:
obtain rfl | hy := eq_or_ne y 0
  · simp
  obtain rfl | hx := eq_or_ne x 0
  · simp [angle_neg_right, angle_self hy]
  obtain rfl | hxy := eq_or_ne x y
  · simp [angle_self hx]
  have h_sin (x y : V) (hx : x ≠ 0) (hy : y ≠ 0) :
      Real.sin (angle x y) = √(⟪x, x⟫ * ⟪y, y⟫ - ⟪x, y⟫ * ⟪x, y⟫) / (‖x‖ * ‖y‖) := by
    simp [field, mul_assoc, sin_angle_mul_norm_mul_norm]
  rw [h_sin x y hx hy, h_sin y (x - y) hy (sub_ne_zero_of_ne hxy)]
  simp only [inner_sub_left, inner_sub_right, real_inner_comm x y]
  have hsub : x - y ≠ 0 := sub_ne_zero_of_ne hxy
  field_simp
  ring_nf

Goal state after:
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
⊢ (r * 2 / 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

pp: case h
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 -ᵥ p₁ ≠ 0

Tactic:
mul_div_cancel_right₀ _ (two_ne_zero' ℝ)

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
⊢ r • («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

case h
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 -ᵥ p₁ ≠ 0