Theorems · Theorem · real analysis

isMinOn_Iio_of_deriv

∀ {f : ℝ → ℝ} {b c : ℝ},
  ContinuousAt f b →
    DifferentiableOn ℝ f (Set.Iio b) →
      DifferentiableOn ℝ f (Set.Ioo b c) →
        (∀ x ∈ Set.Iio b, deriv f x ≤ 0) → (∀ x ∈ Set.Ioo b c, 0 ≤ deriv f x) → IsMinOn f (Set.Iio c) b

Suppose f : ℝ → ℝ is continuous at b, the derivative f' is nonpositive on Iio b and nonnegative on Ioo b c. Then f attains its minimum on Iio c at b.

Defined in

Mathlib.Analysis.Calculus.DerivativeTest

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Foundations

Depth 192 from the axioms · uses propext, Classical.choice, Quot.sound