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VJIMC 2015 Category II, Problem 1

Source: VJIMC2015

August 10, 2015
Matriceslinear algebracollege contests

Problem Statement

Problem 1 Let AA and BB be two 3×33 \times 3 matrices with real entries. Prove that A(A1+(B1A)1)1=ABA , A-(A^{-1} +(B^{-1}-A)^{-1})^{-1} =ABA\ , provided all the inverses appearing on the left-hand side of the equality exist.