Lagrange's theorem and its converse

Whole-channel inclusion: MathLogic is an honest teaching channel (title sample + 3 transcripts read: The one sample with a transcript is a structured math lecture deriving moment of inertia formulas, consistent with the channel's teaching verdict.); this title passed a strict title check (sonnet) after a labelling pass.

A 17-minute video from MathLogic: “Lagrange's theorem and its converse”.

Video by MathLogic, played through YouTube's embedded player.