@@ -200,47 +200,6 @@ lemma isMaxOn_of_deriv_univ {f : ℝ → ℝ} {b : ℝ} (hb : ContinuousAt f b)
200200 (antitoneOn_of_deriv_nonpos (convex_Ici b) (continuousOn_Ici hb hd₁) (by simp_all)
201201 (by simp_all))
202202
203- -- After isMinOn_of_deriv_Ici, before isLocalMin_of_deriv_Ioo
204-
205- /-- Suppose `b < c`, `f : ℝ → ℝ` is continuous at `b`, the derivative `f'` is nonpositive on
206- `(-∞, b)`, and the derivative `f'` is nonnegative on `(b, c)`. Then `f` attains its minimum on
207- `(-∞, c)` at `b`. -/
208- lemma isMinOn_of_deriv_Iio {f : ℝ → ℝ} {b c : ℝ} (g₁ : b < c) (hb : ContinuousAt f b)
209- (hd₀ : DifferentiableOn ℝ f (Iio b)) (hd₁ : DifferentiableOn ℝ f (Ioo b c))
210- (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 ) (h₁ : ∀ x ∈ Ioo b c, 0 ≤ deriv f x) :
211- IsMinOn f (Iio c) b :=
212- isMinOn_of_anti_mono_Iio g₁
213- (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
214- (by simp_all))
215- (monotoneOn_of_deriv_nonneg (convex_Ico b c) (continuousOn_Ico g₁ hb hd₁) (by simp_all)
216- (by simp_all))
217-
218- /-- Suppose `b ≤ c`, `f : ℝ → ℝ` is continuous at `b` and `c`, the derivative `f'` is nonpositive
219- on `(-∞, b)`, and the derivative `f'` is nonnegative on `(b, c)`. Then `f` attains its minimum on
220- `(-∞, c]` at `b`. -/
221- lemma isMinOn_of_deriv_Iic {f : ℝ → ℝ} {b c : ℝ} (g₁ : b ≤ c) (hb : ContinuousAt f b)
222- (hc : ContinuousAt f c) (hd₀ : DifferentiableOn ℝ f (Iio b))
223- (hd₁ : DifferentiableOn ℝ f (Ioo b c)) (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 )
224- (h₁ : ∀ x ∈ Ioo b c, 0 ≤ deriv f x) : IsMinOn f (Iic c) b :=
225- isMinOn_of_anti_mono_Iic g₁
226- (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
227- (by simp_all))
228- (monotoneOn_of_deriv_nonneg (convex_Icc b c) (continuousOn_Icc g₁ hb hc hd₁) (by simp_all)
229- (by simp_all))
230-
231- /-- Suppose `f : ℝ → ℝ` is continuous at `b`, the derivative `f'` is nonpositive on `(-∞, b)`,
232- and the derivative `f'` is nonnegative on `(b, ∞)`. Then `f` attains its minimum on `ℝ`
233- at `b`. -/
234- lemma isMinOn_of_deriv_univ {f : ℝ → ℝ} {b : ℝ} (hb : ContinuousAt f b)
235- (hd₀ : DifferentiableOn ℝ f (Iio b)) (hd₁ : DifferentiableOn ℝ f (Ioi b))
236- (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 ) (h₁ : ∀ x ∈ Ioi b, 0 ≤ deriv f x) :
237- IsMinOn f univ b :=
238- isMinOn_of_anti_mono_univ
239- (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
240- (by simp_all))
241- (monotoneOn_of_deriv_nonneg (convex_Ici b) (continuousOn_Ici hb hd₁) (by simp_all)
242- (by simp_all))
243-
244203/-- The First-Derivative Test from calculus, maxima version.
245204Suppose `a < b < c`, `f : ℝ → ℝ` is continuous at `b`,
246205the derivative `f'` is nonnegative on `(a,b)`, and
@@ -332,6 +291,45 @@ lemma isMinOn_of_deriv_Ici {f : ℝ → ℝ} {a b : ℝ} (g₀ : a ≤ b) (ha :
332291 (monotoneOn_of_deriv_nonneg (convex_Ici b) (continuousOn_Ici hb hd₁) (by simp_all)
333292 (by simp_all))
334293
294+ /-- Suppose `b < c`, `f : ℝ → ℝ` is continuous at `b`, the derivative `f'` is nonpositive on
295+ `(-∞, b)`, and the derivative `f'` is nonnegative on `(b, c)`. Then `f` attains its minimum on
296+ `(-∞, c)` at `b`. -/
297+ lemma isMinOn_of_deriv_Iio {f : ℝ → ℝ} {b c : ℝ} (g₁ : b < c) (hb : ContinuousAt f b)
298+ (hd₀ : DifferentiableOn ℝ f (Iio b)) (hd₁ : DifferentiableOn ℝ f (Ioo b c))
299+ (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 ) (h₁ : ∀ x ∈ Ioo b c, 0 ≤ deriv f x) :
300+ IsMinOn f (Iio c) b :=
301+ isMinOn_of_anti_mono_Iio g₁
302+ (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
303+ (by simp_all))
304+ (monotoneOn_of_deriv_nonneg (convex_Ico b c) (continuousOn_Ico g₁ hb hd₁) (by simp_all)
305+ (by simp_all))
306+
307+ /-- Suppose `b ≤ c`, `f : ℝ → ℝ` is continuous at `b` and `c`, the derivative `f'` is nonpositive
308+ on `(-∞, b)`, and the derivative `f'` is nonnegative on `(b, c)`. Then `f` attains its minimum on
309+ `(-∞, c]` at `b`. -/
310+ lemma isMinOn_of_deriv_Iic {f : ℝ → ℝ} {b c : ℝ} (g₁ : b ≤ c) (hb : ContinuousAt f b)
311+ (hc : ContinuousAt f c) (hd₀ : DifferentiableOn ℝ f (Iio b))
312+ (hd₁ : DifferentiableOn ℝ f (Ioo b c)) (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 )
313+ (h₁ : ∀ x ∈ Ioo b c, 0 ≤ deriv f x) : IsMinOn f (Iic c) b :=
314+ isMinOn_of_anti_mono_Iic g₁
315+ (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
316+ (by simp_all))
317+ (monotoneOn_of_deriv_nonneg (convex_Icc b c) (continuousOn_Icc g₁ hb hc hd₁) (by simp_all)
318+ (by simp_all))
319+
320+ /-- Suppose `f : ℝ → ℝ` is continuous at `b`, the derivative `f'` is nonpositive on `(-∞, b)`,
321+ and the derivative `f'` is nonnegative on `(b, ∞)`. Then `f` attains its minimum on `ℝ`
322+ at `b`. -/
323+ lemma isMinOn_of_deriv_univ {f : ℝ → ℝ} {b : ℝ} (hb : ContinuousAt f b)
324+ (hd₀ : DifferentiableOn ℝ f (Iio b)) (hd₁ : DifferentiableOn ℝ f (Ioi b))
325+ (h₀ : ∀ x ∈ Iio b, deriv f x ≤ 0 ) (h₁ : ∀ x ∈ Ioi b, 0 ≤ deriv f x) :
326+ IsMinOn f univ b :=
327+ isMinOn_of_anti_mono_univ
328+ (antitoneOn_of_deriv_nonpos (convex_Iic b) (continuousOn_Iic hb hd₀) (by simp_all)
329+ (by simp_all))
330+ (monotoneOn_of_deriv_nonneg (convex_Ici b) (continuousOn_Ici hb hd₁) (by simp_all)
331+ (by simp_all))
332+
335333/-- The First-Derivative Test from calculus, minima version. -/
336334lemma isLocalMin_of_deriv_Ioo {f : ℝ → ℝ} {a b c : ℝ} (g₀ : a < b) (g₁ : b < c)
337335 (h : ContinuousAt f b) (hd₀ : DifferentiableOn ℝ f (Ioo a b))
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