TITLE:
Two Nonzero Component Lemma and Matrix Trigonometry
AUTHORS:
Morteza Seddighin
KEYWORDS:
Matrix Trigonometry
JOURNAL NAME:
Advances in Linear Algebra & Matrix Theory,
Vol.7 No.1,
February
15,
2017
ABSTRACT: In this paper we show that the author’s Two Nonzero Lemma (TNCL) can be applied to present a simple proof for a very useful equality which was first proved by Karl Gustafson in 1968. Gustafson used Hilbert space methods, including convexity of the Hilbert space norm, to prove this identity which was the basis of his matrix trigonometry. By applying TNCL, we will reduce the problem to a simple problem of ordinary calculus.