Alphabeta Math
DefinitionDefinition: Literature-sourcedProof: Not applicableaudited 2026-08-03
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

The principal inverse tangent arctan⁡:R→(−π/2,π/2)

Definition

By Tangent is a continuous strictly increasing bijection from (−π/2,π/2) onto R, tangent restricts to a continuous strictly increasing bijection

tan⁡:(−π/2,π/2)⟶R.

Its inverse is the principal inverse tangent

arctan⁡:R⟶(−π/2,π/2).

Thus tan⁡(arctan⁡y)=y for every real y, while arctan⁡(tan⁡x)=x precisely for x in the displayed principal interval. The inverse is continuous and strictly increasing by Continuous inverse theorem: a continuous injective f on an interval I is a bijection onto the order-convex set f[I], and the inverse g:f[I]→I is continuous and strictly monotone in the same sense as f.

Depends on

Dependency tree · 2 levels

Sources