mathlib-initiative/mathlib-tactics huggingface dataset:
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
h₃₂ : p₃ ≠ p₂
h₄₂ : p₄ ≠ p₂
ha' : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄)
hs' : line[ℝ, p₁, p₂].SOppSide p₄ ((AffineEquiv.pointReflection ℝ p₂) p₄)
h : ∠ p₁ p₂ p₃ = π - ∠ p₁ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄) / 2
⊢ ∠ p₁ p₂ p₃ = (∠ p₁ p₂ p₄ + π) / 2

Tactic:
angle_pointReflection_right

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
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
h₃₂ : p₃ ≠ p₂
h₄₂ : p₄ ≠ p₂
ha' : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄)
hs' : line[ℝ, p₁, p₂].SOppSide p₄ ((AffineEquiv.pointReflection ℝ p₂) p₄)
h : ∠ p₁ p₂ p₃ = π - (π - ∠ p₁ p₂ p₄) / 2
⊢ ∠ p₁ p₂ p₃ = (∠ p₁ p₂ p₄ + π) / 2
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].SOppSide p₃ p₄
h₃₂ : p₃ ≠ p₂
h₄₂ : p₄ ≠ p₂
ha' : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄)
hs' : line[ℝ, p₁, p₂].SOppSide p₄ ((AffineEquiv.pointReflection ℝ p₂) p₄)
h : ∠ p₁ p₂ p₃ = ∠ p₁ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄) / 2
⊢ ∠ p₁ p₂ p₃ = (π - ∠ p₁ p₂ p₄) / 2

Tactic:
angle_pointReflection_right

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
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].SOppSide p₃ p₄
h₃₂ : p₃ ≠ p₂
h₄₂ : p₄ ≠ p₂
ha' : ∡ p₁ p₂ p₃ = ∡ p₃ p₂ ((AffineEquiv.pointReflection ℝ p₂) p₄)
hs' : line[ℝ, p₁, p₂].SOppSide p₄ ((AffineEquiv.pointReflection ℝ p₂) p₄)
h : ∠ p₁ p₂ p₃ = (π - ∠ p₁ p₂ p₄) / 2
⊢ ∠ p₁ p₂ p₃ = (π - ∠ p₁ p₂ p₄) / 2
Module: Mathlib.Geometry.Euclidean.Angle.Bisector

Goal state before:
pp: case e_a
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
h₂ : p₁ ≠ p₂
h' : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = p₁
hp : p ≠ ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
hpm : p ∉ line[ℝ, p₁, p₂]
h : inner ℝ (p -ᵥ p₁) (p₃ -ᵥ p₁) = 0
r : ℝ
⊢ r * inner ℝ (p -ᵥ p₁) (p₁ -ᵥ p₃) = 0

Tactic:
← inner_neg_neg,

Goal state after:
case e_a
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
h₂ : p₁ ≠ p₂
h' : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = p₁
hp : p ≠ ↑((orthogonalProjection line[ℝ, p₁, p₂]) p)
hpm : p ∉ line[ℝ, p₁, p₂]
h : inner ℝ (p -ᵥ p₁) (p₃ -ᵥ p₁) = 0
r : ℝ
⊢ r * inner ℝ (-(p -ᵥ p₁)) (-(p₁ -ᵥ p₃)) = 0
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 p₁ p₂ p₃ : P
h₂ : p₁ ≠ p₂
h : 2 • ∡ p₂ p₁ p = 2 • ∡ p p₁ p₃
h' : ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = p₁
⊢ dist p ↑((orthogonalProjection line[ℝ, p₁, p₂]) p) = dist p ↑((orthogonalProjection line[ℝ, p₁, p₃]) p)

Tactic:
by
  obtain rfl | hp := eq_or_ne p p₁
  · rw [h', dist_self, zero_eq_dist, eq_comm, orthogonalProjection_eq_self_iff]
    exact left_mem_affineSpan_pair _ _ _
  · rw [← h'] at h hp
    have hpm : p ∉ line[ℝ, p₁, p₂] := orthogonalProjection_eq_self_iff.not.1 (Ne.symm hp)
    rw [two_zsmul_oangle_orthogonalProjection_self _ hpm (right_mem_affineSpan_pair _ _ _)
          (h'.symm ▸ h₂.symm), eq_comm, oangle, Real.Angle.two_zsmul_eq_pi_iff, h'] at h
    replace h := (Orientation.eq_zero_or_oangle_eq_iff_inner_eq_zero _).1 (.inr (.inr h))
    congr 1
    rw [h', eq_comm, coe_orthogonalProjection_eq_iff_mem]
    refine ⟨left_mem_affineSpan_pair _ _ _, ?_⟩
    rw [Submodule.mem_orthogonal']
    intro u hu
    rw [direction_affineSpan, mem_vectorSpan_pair] at hu
    rcases hu with ⟨r, rfl⟩
    rw [inner_smul_right, ← inner_neg_neg, inner_neg_left]
    simp [h]

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

Goal state before:
pp: case refine_2
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
s : Sphere P
as : AffineSubspace ℝ P
inst✝¹ : Nonempty ↥as
inst✝ : as.direction.HasOrthogonalProjection
h : s.IsTangentAt (↑((orthogonalProjection as) s.center)) as
⊢ Metric.infDist s.center ↑as = s.radius

Tactic:
h.isTangent.infDist_eq_radius

Goal state after:
case refine_2
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
s : Sphere P
as : AffineSubspace ℝ P
inst✝¹ : Nonempty ↥as
inst✝ : as.direction.HasOrthogonalProjection
h : s.IsTangentAt (↑((orthogonalProjection as) s.center)) as
⊢ s.radius = s.radius
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)
⊢ SignType.sign (s.excenterWeights ∅ i) = 1

Tactic:
by
  rw [sign_eq_one_iff]
  exact s.excenterWeights_empty_pos i

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)
h :
  (s.height i)⁻¹ *
      ∑ i_1, ⟪s.points i -ᵥ s.altitudeFoot i, (s.height i_1)⁻¹ ^ 2 • (s.points i_1 -ᵥ s.altitudeFoot i_1)⟫ =
    (s.height i)⁻¹ * ⟪s.points i -ᵥ s.altitudeFoot i, 0⟫
⊢ ∑ x,
      ⟪s.points i -ᵥ s.altitudeFoot i, s.points x -ᵥ s.altitudeFoot x⟫ /
          (dist (s.points i) (s.altitudeFoot i) * dist (s.points x) (s.altitudeFoot x)) *
        (dist (s.points x) (s.altitudeFoot x))⁻¹ =
    0

Tactic:
Finset.mul_sum

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)
h :
  ∑ i_1,
      (s.height i)⁻¹ * ⟪s.points i -ᵥ s.altitudeFoot i, (s.height i_1)⁻¹ ^ 2 • (s.points i_1 -ᵥ s.altitudeFoot i_1)⟫ =
    (s.height i)⁻¹ * ⟪s.points i -ᵥ s.altitudeFoot i, 0⟫
⊢ ∑ x,
      ⟪s.points i -ᵥ s.altitudeFoot i, s.points x -ᵥ s.altitudeFoot x⟫ /
          (dist (s.points i) (s.altitudeFoot i) * dist (s.points x) (s.altitudeFoot x)) *
        (dist (s.points x) (s.altitudeFoot x))⁻¹ =
    0
Module: Mathlib.Geometry.Euclidean.Incenter

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
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ (s.reindex e).incenter = s.incenter

Tactic:
simp_rw [incenter, exsphere_reindex]

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
m n : ℕ
inst✝¹ : NeZero m
inst✝ : NeZero n
s : Simplex ℝ P n
e : Fin (n + 1) ≃ Fin (m + 1)
⊢ (s.exsphere (Finset.map e.symm.toEmbedding ∅)).center = (s.exsphere ∅).center
Module: Mathlib.Geometry.Euclidean.Triangle

Goal state before:
pp: case neg
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y : V
hpi : angle x y ≠ π
hxy : ¬x = y
h : ‖x‖ - ‖y‖ = ⟪x, y⟫ * (‖x‖⁻¹ - ‖y‖⁻¹)
hx0 : ¬x = 0
⊢ ‖x‖ = ‖y‖

Tactic:
· by_cases hy0 : y = 0
      · rw [hy0, norm_zero, inner_zero_right, zero_mul, sub_zero] at h
        rw [hy0, norm_zero, h]
      · rw [inv_sub_inv (fun hz => hx0 (norm_eq_zero.1 hz)) fun hz => hy0 (norm_eq_zero.1 hz), ←
          neg_sub, ← mul_div_assoc, mul_comm, mul_div_assoc, ← mul_neg_one] at h
        symm
        by_contra hyx
        replace h := (mul_left_cancel₀ (sub_ne_zero_of_ne hyx) h).symm
        rw [real_inner_div_norm_mul_norm_eq_neg_one_iff, ← angle_eq_pi_iff] at h
        exact hpi h

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

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
ι : Type u_3
hne : Nonempty ι
inst✝ : Finite ι
p : ι → P
ha : AffineIndependent ℝ p
val✝ : Fintype ι
m : ℕ
hn : Fintype.card ι = m + 1 + 1
i : ι
ι2 : Type (max 0 u_3) := { x // x ≠ i }
hc : Fintype.card ι2 = m + 1
this : Nonempty ι2
ha2 : AffineIndependent ℝ fun i2 ↦ p ↑i2
hm :
  ∃! cs,
    cs.center ∈ affineSpan ℝ (Set.range fun i2 ↦ p ↑i2) ∧ (Set.range fun i2 ↦ p ↑i2) ⊆ Metric.sphere cs.center cs.radius
⊢ Set.range p = insert (p i) (Set.range fun i2 ↦ p ↑i2)

Tactic:
← Set.image_eq_range,

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
ι : Type u_3
hne : Nonempty ι
inst✝ : Finite ι
p : ι → P
ha : AffineIndependent ℝ p
val✝ : Fintype ι
m : ℕ
hn : Fintype.card ι = m + 1 + 1
i : ι
ι2 : Type (max 0 u_3) := { x // x ≠ i }
hc : Fintype.card ι2 = m + 1
this : Nonempty ι2
ha2 : AffineIndependent ℝ fun i2 ↦ p ↑i2
hm :
  ∃! cs,
    cs.center ∈ affineSpan ℝ (Set.range fun i2 ↦ p ↑i2) ∧ (Set.range fun i2 ↦ p ↑i2) ⊆ Metric.sphere cs.center cs.radius
⊢ Set.range p = insert (p i) (p '' {x | x ≠ i})
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
p : P
hp : p ∈ affineSpan ℝ (Set.range s.points)
r : ℝ
hr : ∀ (i : Fin (n + 1)), dist (s.points i) p = r
h :
  { center := p, radius := r }.center ∈ affineSpan ℝ (Set.range s.points) ∧
      Set.range s.points ⊆ Metric.sphere { center := p, radius := r }.center { center := p, radius := r }.radius →
    { center := p, radius := r } = s.circumsphere
⊢ p = s.circumcenter

Tactic:
simp only [hp, hr, forall_const, subset_sphere (s := ⟨p, r⟩), Sphere.ext_iff,
    Set.forall_mem_range, mem_sphere, true_and] at h

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
p : P
hp : p ∈ affineSpan ℝ (Set.range s.points)
r : ℝ
hr : ∀ (i : Fin (n + 1)), dist (s.points i) p = r
h : p = s.circumsphere.center ∧ r = s.circumsphere.radius
⊢ p = s.circumcenter
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
p : P
hp : p ∈ affineSpan ℝ (Set.range s.points)
r : ℝ
hr : ∀ (i : Fin (n + 1)), dist (s.points i) p = r
h :
  { center := p, radius := r }.center ∈ affineSpan ℝ (Set.range s.points) ∧
      Set.range s.points ⊆ Metric.sphere { center := p, radius := r }.center { center := p, radius := r }.radius →
    { center := p, radius := r } = s.circumsphere
⊢ r = s.circumradius

Tactic:
simp only [hp, hr, forall_const, subset_sphere (s := ⟨p, r⟩), Sphere.ext_iff,
    Set.forall_mem_range, mem_sphere, true_and] at h

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
p : P
hp : p ∈ affineSpan ℝ (Set.range s.points)
r : ℝ
hr : ∀ (i : Fin (n + 1)), dist (s.points i) p = r
h : p = s.circumsphere.center ∧ r = s.circumsphere.radius
⊢ r = s.circumradius
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
S : AffineSubspace ℝ P
hS : affineSpan ℝ (Set.range s.points) ≤ S
⊢ s.circumcenter = ↑(s.restrict S hS).circumcenter

Tactic:
have : Nonempty S := Nonempty.map (AffineSubspace.inclusion hS) inferInstance

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
S : AffineSubspace ℝ P
hS : affineSpan ℝ (Set.range s.points) ≤ S
this : Nonempty ↥S
⊢ s.circumcenter = ↑(s.restrict S hS).circumcenter
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
S : AffineSubspace ℝ P
hS : affineSpan ℝ (Set.range s.points) ≤ S
⊢ s.circumradius = (s.restrict S hS).circumradius

Tactic:
have : Nonempty S := Nonempty.map (AffineSubspace.inclusion hS) inferInstance

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
S : AffineSubspace ℝ P
hS : affineSpan ℝ (Set.range s.points) ≤ S
this : Nonempty ↥S
⊢ s.circumradius = (s.restrict S hS).circumradius
Module: Mathlib.Geometry.Euclidean.Triangle

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
a b c : P
hbc : ¬b = c
m : P := midpoint ℝ b c
this : dist b c ≠ 0
hm :
  dist a b ^ 2 * (2⁻¹ * dist b c) + dist a c ^ 2 * (2⁻¹ * dist b c) =
    dist b c * (dist a (midpoint ℝ b c) ^ 2 + 2⁻¹ * dist b c * (2⁻¹ * dist b c))
⊢ dist a b ^ 2 + dist a c ^ 2 = 2 * (dist a (midpoint ℝ b c) ^ 2 + (dist b c / 2) ^ 2)

Tactic:
calc
      dist a b ^ 2 + dist a c ^ 2 = 2 / dist b c * (dist a b ^ 2 *
        ((2 : ℝ)⁻¹ * dist b c) + dist a c ^ 2 * (2⁻¹ * dist b c)) := by
        field
      _ = 2 * (dist a (midpoint ℝ b c) ^ 2 + (dist b c / 2) ^ 2) := by
        rw [hm]
        field

Goal state after:
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
h₂₃₁ : ∠ p₂ p₃ p₁ ≤ ∠ p₁ p₂ p₃
h₃₁₂ : ∠ p₃ p₁ p₂ ≤ ∠ p₁ p₂ p₃
⊢ π / 3 ≤ ∠ p₁ p₂ p₃

Tactic:
by
  by_cases h : p₂ = p₁
  · rw [h, angle_self_left]
    linarith [Real.pi_pos]
  · linarith [angle_add_angle_add_angle_eq_pi p₃ h]

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

Goal state before:
pp: case neg
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y z : V
hx : ‖x‖ = 1
hy : ‖y‖ = 1
hz : ‖z‖ = 1
H : angle x z ≠ π
H0 : angle x z = angle x y + angle y z
H1 : ¬angle x z = 0
Hxz : Real.sin (angle x z) ≠ 0
H2 : ¬angle x y = 0
H3 : ¬angle y z = 0
H4 : ¬angle x y = π
H5 : ¬angle y z = π
H6 :
  ⟪x, z⟫ =
    Real.cos (angle y z) * (Real.cos (angle x y) * 1 ^ 2) + Real.cos (angle y z) * (Real.sin (angle x y) * 0) +
      (Real.sin (angle y z) * (Real.cos (angle x y) * 0) +
        Real.sin (angle y z) *
          (Real.sin (angle x y) * ⟪NormedSpace.normalize (ortho y x), NormedSpace.normalize (ortho y z)⟫))
⊢ Real.sin (angle x z) • y = Real.sin (angle y z) • x + Real.sin (angle x y) • z

Tactic:
simp only [one_pow, mul_one, mul_zero, add_zero, zero_add] at H6

Goal state after:
case neg
V : Type u_1
inst✝¹ : NormedAddCommGroup V
inst✝ : InnerProductSpace ℝ V
x y z : V
hx : ‖x‖ = 1
hy : ‖y‖ = 1
hz : ‖z‖ = 1
H : angle x z ≠ π
H0 : angle x z = angle x y + angle y z
H1 : ¬angle x z = 0
Hxz : Real.sin (angle x z) ≠ 0
H2 : ¬angle x y = 0
H3 : ¬angle y z = 0
H4 : ¬angle x y = π
H5 : ¬angle y z = π
H6 :
  ⟪x, z⟫ =
    Real.cos (angle y z) * Real.cos (angle x y) +
      Real.sin (angle y z) *
        (Real.sin (angle x y) * ⟪NormedSpace.normalize (ortho y x), NormedSpace.normalize (ortho y z)⟫)
⊢ Real.sin (angle x z) • y = Real.sin (angle y z) • x + Real.sin (angle x y) • z
Module: Mathlib.Geometry.Euclidean.Incenter

Goal state before:
pp: case mp
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
signs : Finset (Fin (n + 1))
i : Fin (n + 1)
w : Fin (n + 1) → ℝ
hw : ∑ j, w j = 1
⊢ (Finset.affineCombination ℝ Finset.univ s.points) w = s.touchpoint signs i → w = s.touchpointWeights signs i

Tactic:
rw [← s.affineCombination_touchpointWeights]

Goal state after:
case mp
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
signs : Finset (Fin (n + 1))
i : Fin (n + 1)
w : Fin (n + 1) → ℝ
hw : ∑ j, w j = 1
⊢ (Finset.affineCombination ℝ Finset.univ s.points) w =
      (Finset.affineCombination ℝ Finset.univ s.points) (s.touchpointWeights signs i) →
    w = s.touchpointWeights signs i
Module: Mathlib.Geometry.Euclidean.NinePointCircle

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 : Triangle ℝ P
i : Fin 3
⊢ s.points i -ᵥ s.orthocenter ∈ (vectorSpan ℝ (s.points '' {i}ᶜ))ᗮ

Tactic:
refine Set.mem_of_mem_of_subset ?_ (s.vectorSpan_isOrtho_altitude_direction i).ge

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 : Triangle ℝ P
i : Fin 3
⊢ s.points i -ᵥ s.orthocenter ∈ ↑(Simplex.altitude s i).direction
Module: Mathlib.Geometry.Euclidean.MongePoint

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
n : ℕ
s : Simplex ℝ P (n + 2)
i₁ i₂ : Fin (n + 3)
h : ¬i₁ = i₂
hs : ∑ i, (pointWeightsWithCircumcenter i₁ - pointWeightsWithCircumcenter i₂) i = 0
fs : Finset (Fin (n + 3)) := {i₁, i₂}
hfs : ∀ i ∉ fs, i ≠ i₁ ∧ i ≠ i₂
⊢ -(∑ x ∈ fs,
                (if True ∨ i₁ = i₂ then (↑(n + 1))⁻¹ else 0) * ((if x = i₁ then 1 else 0) - if x = i₂ then 1 else 0) *
                  (dist (s.points i₁) (s.points x) * dist (s.points i₁) (s.points x)) +
              (if True ∨ i₁ = i₂ then (↑(n + 1))⁻¹ else 0) * (0 - 0) *
                (dist (s.points i₁) s.circumcenter * dist (s.points i₁) s.circumcenter) +
            (∑ x ∈ fs,
                (if i₂ = i₁ ∨ True then (↑(n + 1))⁻¹ else 0) * ((if x = i₁ then 1 else 0) - if x = i₂ then 1 else 0) *
                  (dist (s.points i₂) (s.points x) * dist (s.points i₂) (s.points x)) +
              (if i₂ = i₁ ∨ True then (↑(n + 1))⁻¹ else 0) * (0 - 0) *
                (dist (s.points i₂) s.circumcenter * dist (s.points i₂) s.circumcenter)) +
          (-2 / ↑(n + 1) * ((if True then 1 else 0) - if i₁ = i₂ then 1 else 0) *
                (dist s.circumcenter (s.points i₁) * dist s.circumcenter (s.points i₁)) +
              -2 / ↑(n + 1) * ((if i₂ = i₁ then 1 else 0) - if True then 1 else 0) *
                (dist s.circumcenter (s.points i₂) * dist s.circumcenter (s.points i₂)) +
            -2 / ↑(n + 1) * (0 - 0) * (dist s.circumcenter s.circumcenter * dist s.circumcenter s.circumcenter))) /
      2 =
    0

Tactic:
simp_rw [fs, sum_insert (notMem_singleton.2 h), sum_singleton]
        simp [h, Ne.symm h, dist_comm (s.points i₁)]

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

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
v : V
⊢ s.secondInter p v = p ↔ ⟪v, p -ᵥ s.center⟫ = 0

Tactic:
refine ⟨fun hp => ?_, fun hp => ?_⟩
  · by_cases hv : v = 0
    · simp [hv]
    rwa [Sphere.secondInter, eq_comm, eq_vadd_iff_vsub_eq, vsub_self, eq_comm, smul_eq_zero,
      or_iff_left hv, div_eq_zero_iff, inner_self_eq_zero, or_iff_left hv, mul_eq_zero,
      or_iff_right (by simp : (-2 : ℝ) ≠ 0)] at hp
  · rw [Sphere.secondInter, hp, mul_zero, zero_div, zero_smul, zero_vadd]

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

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
s : Sphere P
p a b : P
hp : p ∈ line[ℝ, a, b]
ha : a ∈ s
hb : b ∈ s
⊢ dist p a * dist p b = |s.power p|

Tactic:
have hq : dist a s.center = dist b s.center := by
    rw [mem_sphere.mp ha, mem_sphere.mp hb]
  rw [dist_comm p a, dist_comm p b, mul_dist_eq_abs_sub_sq_dist hp hq,
    mem_sphere.mp hb, power, abs_sub_comm]

Goal state after:
Module: Mathlib.Geometry.Manifold.Algebra.SmoothFunctions

Goal state before:
pp: 𝕜 : Type u_1
inst✝²¹ : NontriviallyNormedField 𝕜
E : Type u_2
inst✝²⁰ : NormedAddCommGroup E
inst✝¹⁹ : NormedSpace 𝕜 E
E' : Type u_3
inst✝¹⁸ : NormedAddCommGroup E'
inst✝¹⁷ : NormedSpace 𝕜 E'
H : Type u_4
inst✝¹⁶ : TopologicalSpace H
I : ModelWithCorners 𝕜 E H
H' : Type u_5
inst✝¹⁵ : TopologicalSpace H'
I' : ModelWithCorners 𝕜 E' H'
N : Type u_6
inst✝¹⁴ : TopologicalSpace N
inst✝¹³ : ChartedSpace H N
E'' : Type u_7
inst✝¹² : NormedAddCommGroup E''
inst✝¹¹ : NormedSpace 𝕜 E''
H'' : Type u_8
inst✝¹⁰ : TopologicalSpace H''
I'' : ModelWithCorners 𝕜 E'' H''
N' : Type u_9
inst✝⁹ : TopologicalSpace N'
inst✝⁸ : ChartedSpace H'' N'
n : ℕ∞ω
G' : Type u_10
inst✝⁷ : Monoid G'
inst✝⁶ : TopologicalSpace G'
inst✝⁵ : ChartedSpace H' G'
inst✝⁴ : ContMDiffMul I' n G'
G'' : Type u_11
inst✝³ : Monoid G''
inst✝² : TopologicalSpace G''
inst✝¹ : ChartedSpace H'' G''
inst✝ : ContMDiffMul I'' n G''
φ : G' →* G''
hφ : ContMDiff I' I'' n ⇑φ
f g : C^n⟮I, N; I', G'⟯
⊢ ⟨⇑φ ∘ ⇑(f * g), ⋯⟩ = ⟨⇑φ ∘ ⇑f, ⋯⟩ * ⟨⇑φ ∘ ⇑g, ⋯⟩

Tactic:
by ext x; change φ (f x * g x) = φ (f x) * φ (g x); simp

Goal state after:
Module: Mathlib.Geometry.Manifold.IsManifold.InteriorBoundary

Goal state before:
pp: E : Type u_5
H : Type u_6
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace ℝ E
inst✝¹ : NormedAddCommGroup H
inst✝ : NormedSpace ℝ H
f : E → H
x : E
hf : DifferentiableAt ℝ f x
u : Set E
hu : u ∈ 𝓝 x
s : Set H
hs : Convex ℝ s
hs' : IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] s
hs'' : (interior s).Nonempty
hfus : MapsTo f u s
hfx : f x ∉ interior s
F : StrongDual ℝ H
hF : ∀ a ∈ interior s, F a < F (f x)
⊢ MapsTo (⇑F) s (Iic (F (f x)))

Tactic:
rw [← hs'.closure_eq, ← closure_Iio, ← hs.closure_interior_eq_closure_of_nonempty_interior hs'']

Goal state after:
E : Type u_5
H : Type u_6
inst✝³ : NormedAddCommGroup E
inst✝² : NormedSpace ℝ E
inst✝¹ : NormedAddCommGroup H
inst✝ : NormedSpace ℝ H
f : E → H
x : E
hf : DifferentiableAt ℝ f x
u : Set E
hu : u ∈ 𝓝 x
s : Set H
hs : Convex ℝ s
hs' : IsClosed[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] s
hs'' : (interior s).Nonempty
hfus : MapsTo f u s
hfx : f x ∉ interior s
F : StrongDual ℝ H
hF : ∀ a ∈ interior s, F a < F (f x)
⊢ MapsTo (⇑F) (closure[PseudoMetricSpace.toUniformSpace.toTopologicalSpace] (interior s)) (closure (Iio (F (f x))))