Module: Mathlib.Geometry.Euclidean.Angle.Bisector

Goal state before:
pp: case e'_2.e'_3
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 p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
hs : ↑((orthogonalProjection (line[ℝ, p₁, p₂] ⊔ line[ℝ, p₁, p₃])) p) = ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
⊢ {p₁, p₂} = ![p₁, p₂, p₃] '' {0, 1}

pp: case e'_2.e'_4
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 p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
hs : ↑((orthogonalProjection (line[ℝ, p₁, p₂] ⊔ line[ℝ, p₁, p₃])) p) = ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
⊢ {p₁, p₃} = ![p₁, p₂, p₃] '' {0, 2}

pp: case e'_3
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 p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
hs : ↑((orthogonalProjection (line[ℝ, p₁, p₂] ⊔ line[ℝ, p₁, p₃])) p) = ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
⊢ {p₁} = ![p₁, p₂, p₃] '' ({0, 1} ∩ {0, 2})

Tactic:
· simp [Set.image_insert_eq]

Goal state after:
case e'_2.e'_4
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 p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
hs : ↑((orthogonalProjection (line[ℝ, p₁, p₂] ⊔ line[ℝ, p₁, p₃])) p) = ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
⊢ {p₁, p₃} = ![p₁, p₂, p₃] '' {0, 2}

case e'_3
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 p₁ p₂ p₃ : P
ha : AffineIndependent ℝ ![p₁, p₂, p₃]
h : dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
ho : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)
hs : ↑((orthogonalProjection (line[ℝ, p₁, p₂] ⊔ line[ℝ, p₁, p₃])) p) = ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
⊢ {p₁} = ![p₁, p₂, p₃] '' ({0, 1} ∩ {0, 2})