Cauchy-Schwarz: Proof using Jensen's Inequality

We explore a proof of the Cauchy-Schwarz inequality using a version of Jensen's inequality for finite sums. Proof of this version of Jensen's inequality: https://en.wikipedia.org/wiki/Jensen%...) I discovered the proof in this paper: Wu, Hui-Hua, and Wu, Shanhe. Various proofs of the Cauchy-Schwarz inequality. Octogon mathematical magazine 17.1 (2009): 221-229. 00:00 Jensen's Inequality 02:28 Main proof 06:10 Special case