设
b =
1
-1
1
c = (1,1,-1),
则A = bc,A^4 = (bc)(bc)(bc)(bc) = b(cb)(cb)(cb)c = b(cb)^3c.
而cb = -1,故A^4 = b(-1)^3c = -bc = -A =
-1 -1 1
1 1 -1
-1 -1 1
设
b =
1
-1
1
c = (1,1,-1),
则A = bc,A^4 = (bc)(bc)(bc)(bc) = b(cb)(cb)(cb)c = b(cb)^3c.
而cb = -1,故A^4 = b(-1)^3c = -bc = -A =
-1 -1 1
1 1 -1
-1 -1 1