Complex.cos_ne_zero_of_arctan_bounds

∀ {z : ℂ}, z ≠ ↑Real.pi / 2 → -(Real.pi / 2) < z.re → z.re ≤ Real.pi / 2 → Complex.cos z ≠ 0

cos z is nonzero when the bounds in arctan_tan are met (z lies in the vertical strip -π / 2 < z.re < π / 2 and z ≠ π / 2).

Defined in: Mathlib.Analysis.SpecialFunctions.Complex.Arctan
Cited by: 1 results in Mathlib
Foundations: Depth 198 from the axioms · uses propext, Classical.choice, Quot.sound

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